I've only been hit on once by gay men and it was a case of mistaken identity. It was at a halloween party in 2004 and I was dressed as an Abu Ghraib detainee from Iraq, mostly naked wearing just a black hood, a dog collar and leash around my neck, and skin colored underwear with a stuffed dog attached as if it was biting my crotch. Nobody really got the costume - they just assumed it was some sort of fetish thing.
I was literally in a gay bar the only time I was hit on. My friend was the bartender and I'd hang out there with him sometimes. So for all I know, the guy hitting on me was just very desperate.
I sure wasn't hit on any of the other times I was in there.