I'm mostly gay, have composed a symphony and hundreds of other pieces, but I don't know that any of them sound particularly "gay." But I have a few thoughts:
Charles Ives, an early 20th century composer, said that Chopin was so effeminate (gay) that not only did he dress extremely well for the stage, he probably sewed each of his pretty little frocks himself.
Personally, I don't know about any classical music being more preferred by gay men. Tchaikovsky was gay and depressed. It's all through his music. Mozart was probably a closet gay, but married to please his family (and the Church.) Gay chord? Don't know that there could be such a thing.
However, I think "It's Raining Men" by the Weather Girls is a STRONG candidate for gay music (despite it being sung by straight women...) But then, there are probably a lot of other gay anthems in all genres of music also.
Who doesn't associate "YMCA" with gay?
Albinoni really struck a universal chord of pathos in everyone with some of his pieces. I'm not sure it could be touted overly gay.
Cher is gay (friendly). She seems to be an icon of transgendered, luxurious, ostentation. And fun!
Such are my musings...