Baradiel said:
SNIP
And whats the difference between a gay man hitting on you, or a woman hitting on you (if you're a heterosexual man). Its preference. A gay man might be offended and upset when hit on by a woman, just as much as a straight man when he's hit on by a gay man.
I learned from my Anthropology class, and this is probably much less applicable today, that there's a lot more going on to that situation than just what you say. Because of gender roles, women are pretty much expected to say "no" to the initial proposition, and men are expected to continue to pursue after, with varying degrees of stigma attached to the act of saying "yes" to the first advance on the part of the woman. Being hit on puts a man, (in the case of one who gets uncomfortable or upset by being hit on by gays) in the place of the woman, where the only option is to say "no," but declining the proposition, at least in this man's experience, is no way to prevent further propositions. Apparently when women's rights were still being fought for, women would gather in groups and catcall men to demonstrate how uncomfortable it was for women when men did that, and men apparently got quite upset as well.
Basically, what I'm trying to say is that one's gender roles play a significant part in how much being hit on bothers you, and those are kind of hard to blame on someone.