There are at least a few gay men in folk that I can think of, but they all fall under the rather esoteric umbrella of Pagan folk music. The majority of the lesbians I personally know in folk are also Pagans.

Most of the gay men I have ever been close with were more into the club scene and all the music that comes with that. And, as cliche as it sounds, a good majority of them were also really into show tunes.

I think there is a certain amount of our aesthetic taste that comes from what social unit we most identify with. My folk interests come from being a "freak" in high school and being into the works of Tolkien. I loved Jethro Tull and then Medieval music to read my books by. Later, my interest in my Scottish and Irish heritage (which sort of sprang from all the previous, believe it or not) made a clear focus to what folk music I am most attracted to.

I would think that the same likely applies to those who find themselves in a mostly gay or lesbian social setting as well. That their culture helps to shape their tastes.