Okay, so here's the way i look at it:
Yaoi is, if nothing else, generally incredibly niché, with a tendency to be fanservice intended for girls, with wistful men in tragic, tearworthy situations. It's not exactly made for actual gays, and if anything takes a really patronising approach to how they should be represented, and I've seen many a gay couple at comic conventions 'glomped' by short, sweaty yaoi fangirls who freak me the fuck out.
I'm sure there are GOOD stories out there that are yaoi, but I've yet to encounter a single one.
But then I don't exactly hunt this stuff out, because it's awful.
As for the fan-fiction stuff, that's pathetic, whether for manga and anime or even western comics circles. It's people pairing up characters to match their fantasies and insisting that the feelings between the fictional characters are real and that the creators don't have the balls to reveal their true intention. This. is. butt-fuck. insane.
as an aside Yuri can occasionally pull of the non-fanfiction stories, but then their target audience tends to actually be, y'know, actual lesbians as opposed to freaky shut-ins of the opposite gender.
