I've seen this claim made in a variety of situations, but the two most prominent are the following:
1) There's a female original character in a movie or original arc of a TV show based on a book or an anime based on a manga. In said original arc, which was not written or conceived of by the author of the book or manga, the female character is hinted to be the love interest of a male character or openly admits feelings for said male character. When the arc or movie ends, the female character disappears-- since she is not a part of the original book or manga series, she has no part in the rest of the show.
In response to this female character, fans and fanfiction authors react. They dislike this female character because she has come between her male love interest (for the ease of reference, Male 1) and another male friend of his (Male 2). The more immature among them bash her ruthlessly-- something I don't condone, of course, because it's unnecessary and rude. There is a difference between meta/commentary and bashing, naturally, but even the bashing, rude and immature as it may be, is not, so far as I can tell, misogynist. The nature of these situations, at least within my familiarity, is that frankly, Male 1 has a meaningful, long-standing relationship with Male 2, be it a friendship, rivalry, or even hatred. Male 1 and Male 2 have been in the series together for as long as it's existed, and probably longer in the book or manga since these original arcs and movies tend to be dropped down inconveniently in the middle of a story line. What sense does it make, then, for the random female to appear on the scene and, within a relatively short duration, fall hopelessly in love with Male 1? Maybe the pairing does have some merit, maybe the female is more than a canon-sue (which these characters, especially in anime, tend to be), but the fact of the matter stands that she did not exist in the original media and therefore probably does not have as well-developed a relationship with Male 1 as Male 2 does. If the female were, instead, a Male 3, I feel that the same reaction would be merited. It has nothing to do with gender and everything to do with the value of the relationship and the pairing.
Of course, as I mentioned above, bashing the character is rude, and everyone is entitled to her own opinion. If someone likes the female character and wants to write her with Male 1, naturally, it's rude and uncalled for to bash the person's work based on that (or really, at all; is public bashing ever acceptable?) Like as not, it's completely possible to develop the relationship between Male 1 and the female character into something really interesting, and if that is someone's chosen pursuit, I wouldn't judge her for it. But in the long run, is disliking a female character created (sometimes purposefully out of homophobia) to break up a slash ship misogynistic? Often, especially in Japanese works, the female character is an object of sexism in and of herself (as are many Japanese female characters, something which, I think, drives many feminist Japanophiles to slash in the first place) and her creation as a road block between Male 1 and Male 2 is an act of homophobia. In the long run, then, am I a misogynist to see something wrong with this scenario?
Naturally, immature people who lack social awareness will say offensive things, and I'm not arguing that no fan has ever made an offensive, sexist comment along this strain. But the generalization that all fans who dislike the female because she comes between Male 1 and Male 2 is, in my honest and personal opinion, completely incorrect. And honestly, in a situation with the new female, Male 1, and Female 2, fans react with the same uproar.
2) A male character who has been either hinted to be (chain-womanizer, in a heterosexual relationship throughout the series or work, pines for various female characters at various times in canon) or is said openly to be heterosexual is written or depicted in a homosexual relationship in some form of fanwork.
And then everyone is up in arms! This is wrong and disrespectful! Clearly, this male (now Male A, to differentiate from Male 1 above) is only interested in women, and writing him in relationships with men is entirely misogynistic. Just because the author or artist wants slash and finds it "hot," she's sacrificing both the integrity of the character and the honor of women everywhere, because women are just no good to this author. The only people for men are other man, and women are to be tossed to the wayside. Clear sexism.
To which I have a variety of responses, and this first is: sometimes, yes. I agree that there are cases where this seems relatively pointless, but usually they are in fiction or fanworks made up of bad grammar, internet slang, and/or purple prose. By which I mean to say, there are immature writers who will do immature things. I know that when I was 14, I wrote and said things of which I'm not proud.
But to the rest of these works at large, I hardly feel like this is a wound to women everywhere. And my first question is is the only point of female characters to be in relationships? Why is it the end of the world that Female A has been ousted from her relationship with Male A, be it canon, hinted, or simply popular in fandom? Relationships begin and end with great regularity in the real world, and it is my hope that the main goal of those pointing fingers and slinging accusations of misogyny isn't to convince the modern woman that her purpose is to always be in a relationship. Luckily, we no longer live in the 1950s and no longer go to women's colleges to meet a nice boy at the brother school, settle down, and start popping out babies. So if someone writes a fanwork in which Male A is no longer interested in Female A and ends up in a relationship with Male B, is it the end of the world for Female A? Can't Female A go on with her life, and most likely find another meaningful relationship?
But Male A is clearly heterosexual, you say, and you have a point. Male A is said to be heterosexual in canon. But today's society, in great majority, says that everyone is heterosexual, unless they've veered from the "normal" track at some point, and who is to say that Male A hasn't been told that he's straight all his life, and has not ever thought differently? Maybe Male A is a chain womanizer-- clearly, he's into women. But does that mean that he can't be bisexual? Perhaps he's womanizing to convince himself that he's straight rather than face that he's attracted to men. Sexuality in the world of fiction, as far as I'm concerned, is fluid. Just because Male A is in a relationship with Female A in canon does not mean that he could never be interested in Male B. Because it's fiction. These people are not real, and therefore cannot tell us how they feel. If an author wishes to explore a scenario where Male A is in a relationship with Male B, is it misogyny, or is it artistic license? Assuming that Male A doesn't chose to break it off with Female A by insulting all women and saying that only men are worthy of his affections or something of the like, I hardly think that exploring one possible track of action in a character's life has an underlying sexist agenda.
But if the same thing were done with a homosexual character being paired with a female, there would be an uproar of these misogynist fans, wouldn't there? Why is it okay for a heterosexual male character to be portrayed as interested in men when it's not okay for a homosexual male character to be portrayed as interested in women? In my opinion, this is a sticking point, but it comes down to this: unfortunately, our society isn't fair. Heterosexuality is the "norm." Many characters are portrayed as heterosexual in the media because they are expected to be, and whereas the default for most characters is heterosexual, it is a distinct choice on the part of the creator of the canon series to make a character homosexual. So while most characters are portrayed as heterosexual because the creator is not particularly open-minded or didn't want to risk her ratings on creating homosexual characters, homosexual characters are a choice, a statement by the creator that is clearly against the mainstream. And so, often, while making a heterosexual character engage in homosexual activity in fanfiction not only follows the not-unrealistic scenario of a male who grew up being told he was "normal" and assuming he was heterosexual realizing that he might perhaps be attracted to men, it can be seen as an interesting investigation of the characters involved. On the other hand, making an openly-homosexual male character behave in a heterosexual way in fanwork reeks of "normalization," of the author taking the character and "fixing" him towards the "correct" way of heterosexuality. Even if this is not the author's intent, in our current social environment, in my opinion, that is how the piece reads. A homosexual character in our society has clearly had to think about his sexuality and understand his interest in other males, something that is not necessarily a given in heterosexual male characters. Which, of course, is not to say that a homosexual character being written in a heterosexual relationship cannot be interesting, well-written, and inoffensive-- I believe that it can be, and I would definitely not bar such works. But as an explanation as to why I consider one more acceptable than the other, it has little to do with a hatred for women and much more to do with a desire to promote the acceptability and normalcy of homosexuality.
And really, in the long run, is it so unacceptable that Male A should quit his canon relationship with Female A and start one with Female B? Fanfiction is a place for things that are not canon. If Male A is in a canon relationship with Female A and in a fanfiction, he choses to run off with Female B, that is also going against what is canon. Granted, if Male A has always shown fidelity to Female A and is a bigot who hates homosexuality, it would be difficult to mobilize him for a relationship with Male B, but that is a question of characterization rather than feminism. It seems to me that this argument really boils down to, to my great aggravation, is the promotion of homosexuality as acceptable and normal versus the zeal of feminists in fanfiction. And I want to stand on both sides. I realize that female characters often take a beating in the world of fiction at large, and that there are fans who abuse homosexuality and female characters. But there are fans who write any variety of offensive works, and I guess my point in the long run is:
If it's a well-written, well-thought-out fanwork, then the choice to make a character homosexual rather than heterosexual or the choice to ignore and/or dislike an original female character stuck between two male characters with chemistry is not misogynistic. There's a difference between disliking a particular female character and hating all women. There's a difference between wanting to see a male character in a relationship with another male character rather than his canon female love interest and hating women. In the end, we can all respect one another while producing interesting and worthwhile fanworks.
I haven't really been able to make all the points that I'd like to make in this post, nor have I been able to really express myself as eloquently as I would have liked. But the fact holds that I feel like artists and authors and fans should all be able to produce respectful and praise-worthy works and other artists and authors and fans should be able to appreciate them or choose not to appreciate them without jumping to anger. I know the internet is an angry place. I know lots of people have good reason to be angry. But I also think that not all slash fans and writers and artists are misogynists and those who produce offensive work are often ignorant rather than intentionally sexist. Basically, this rant holds for mature and well-written works by people like myself, who strongly believe both in feminism and equality for those of every sexual orientation.
I guess I ought to disclaim this post with the fact that I am, in fact, an active feminist who goes to a women's college. I'm the sort of person who gets unreasonably angry at the Dove chocolate commercials that insinuate that not knitting and sewing is a fault for women and all those cleaning product commercials that specifically target women. Granted, that reeks of self-righteous college student who sits around being angry rather than doing anything, but even if I'm guilty of that, I hardly think that makes me a misogynist. At any rate, I've donated money to women's centers and gone to documentaries and talks by feminist activists in the past, which has to count for something. If you really want to question me and consider me bigoted, I guess that's your right, but I'd appreciate if you'd at least give my point a chance.