Fair enough, but it has also been said that slash denies gay identity (i.e. the stories along the lines of "Blake's not gay, he just has sex with Avon")
I'm not sure this is true any more: early slash in any fandom falls victim to that particular syndrome (originally described for K/S as "Kirk's not gay, he just wants to suck Spock's cock"). In K/S's case, I suppose the writer has to retcon the Dead-Girlfriend-of-the-Week thing *somehow*. Nowadays, there are any number of ways to deal with sexual identity--and slash writing does sometimes deal with them. Read Executrix's Pink-Triangle-Avon stories for writing where sexual identity is the heart of the story, for example. There are quite a few Julia Stamford stories where the politics of sex are an integral part of the story. My stories tend to assume that Blake is gay or bi and Avon is bi and leave it like that, I suppose, because I'm more interested in sex than politics and I find the concept of bisexuality more understandable than the sort of writing you're talking about where neither of them has ever thought about another man until they're in bed together.
and doesn't give much of a voice to lesbians, or address the real
political issues
Am nonplussed. I'm straight myself, but I know of several gay women (including the writer Joanna Russ, viz one of her essays) who have been known to turn on to slash, because slash is a mental kink (like h/c or torture or rape-fantasy) which isn't clearly about what one wants to happen to oneself. Do you also dislike gay men who have a (not necessarily sexual) fantasy about women (Dave W having a thing about Servalan, for example?)?
I'll admit that slash sensibility is much more to do with the women writing it than it's to do with gay sensibility in writing by gay men, but is that really so bad?
Cheers, Pred'x