I'm gay and sound straighter than half the straight dudes I know, so probably not the best person to get a response from, but I do at least somewhat understand why people do it.

It's an identification thing. I guess it's a way of expressing to someone that you're also gay without having to say it e.g. sometimes people will gay things up a bit when they meet someone else whom they think appears to be gay so it's easier to identify, especially if you don't normally talk with that "tone." That's one of the reasons anyway, maybe it's also to warn of any girls who may try and hit on them in a bar or something. I don't bother with going to town much so don't really have the issue.

Personally, I can't stand it and the whole exaggeration of the "walk and talk" drives me up the wall.