I don't think your an ass for not expecting a literal genre change, regardless of sexual orientation. I don't like it when you've got a regular story with regular characters and a regular plot that exhausts itself to the point of only focusing on relationships. The Big Bang Theory had that issue.
But if your issue is only with LGBT springing up I'm a little confused. Not all gay/bi/etc. people are flamboyant or excessively tomboy-ish, so it's kinda hard to say there was no clue of them being gay and then suddenly they're gay. They were just always gay, they just weren't parading it around. For instance, I'm not straight but most people wouldn't guess that. I tell them and they go, "really? You don't look gay."
Also, lots of people are LGBT, they just don't admit to it because of societal reasons. But they usually confide in the acceptance of other LGBT people. So it's very common to see many gays, etc., within a social group. Where there's one gay, there's more lol.