The thing is, most of the gay guys that I know that are "straight acting" (hate to use that, but it's the best-understood term out there) are very conservative about who they hit on. I have a general rule that I won't approach a guy unless he's given me looks at least five times, and even then, I won't flirt unless he starts first. I've probably lost out on meeting some really nice heteroflexible guys that way, but I really have to be careful. If I hit on the wrong (read: insecure about sexuality) guy when he's had just a bit too much to drink, I might end up somewhere painful. This, of course, assumes that I'm not in a situation where the sexual orientation is implied (gay club).
On the easily offended bit, I often make a point of stopping people when they use "gay" to mean, "cheap," "lame," or, "craptastic." I think if people replaced a racial, religious, or ethnic name in that space, people of that race, religion, or ethnicity would (rightfully) get pretty pissed. The only other thing that really pisses me off is "fag." Gay men, not even worthy of being "burned at the stake," were punished as the kindling of witchburnings. They were worth no more than sticks (a synonym for "faggot"). It's the equivalent of calling an African American person a "slave n-word," or telling a Jew to, "Go jump in a gas chamber." You would never say those things because it's well understood that they would be deeply offensive. Is it so incomprehensable that I might react to something like that? Beyond those two big things, I'm really easygoing. It's a delicate issue, because you really have to ask yourself, "How much of it is them being obnoxious, and how much of it is me being uncomfortable with ligitimate, non-offensive behavior?" If you consider a guy wearing "flamy" clothing to be offensive, that's really not his fault. That's your issue.
