That doesn't explain the few times I've been hit on by gay guys. Not even trying. Guys will guys, and naturally a lot more predisponed to going after what they want. Chicks will always be more reserved, due to social conditioning as well as their nature. Even when a girl is interested, it's not likely she'll start anything. It's always on you, as the guy (not that I entirely mind, nowadays).
It's incredible how much one's perspective changes when you're not "thinking with your dick". It's no wonder I didn't care for any chick when guys around me where horndogs for any chick that passed by. I was much cooler, when I was younger (at least in this one regard).