Stereotypes suck. The "gay dancer" stereotype actually probably comes from the patriarchal society's hatred of all that is feminine. In their tiny, pathetic little minds, a man can't "sink" as low as to express any form of femininity, and dancing is traditionally considered a "feminine" thing. I don't think it is, that's just society throughout the ages. If a man --does-- express himself in a way that most in that society would consider feminine (i.e. dancing, taking care of himself to actually look halfway decent for once, etc.) the only way they seem to be able to rationalize his actions is by saying that he's not a "real" man, and therefore, must be gay.
Well, children, there's plenty of straight men, actually, that enjoy dancing and taking care of themselves to look halfway presentable. Oh, and there's plenty of gay men who, by the way, don't care about dancing or about looking nice (one of my friends being of this sort.)
In short, I would like to say, society sucks.