I have half a dozen gay friends in the UK, one of whom is fairly camp, and another more so. The others aren't at all camp.
I've sometimes thought of the camp persona/accent, which some (I believe a minority) of gay men here adopt, as perhaps a reflection of identity or belonging to a group. Perhaps something of a parallel is the Socal teen-speak (eg "toodles", "bff", "totes" etc) - an identifier.
I'm just theorising from my own experience of gay guys though, so who knows.
(And yes, I have known a camp straight guy, but the other camp guys I've seen and heard have all self-identified as gay. As Dr A indicates, I think that a camp persona is far more prevalent in the gay community than not - certainly in my experience in this country).
Edited by vimesey, : Grammar
Could there be any greater conceit, than for someone to believe that the universe has to be simple enough for them to be able to understand it ?