Wow. I just had one of those Blinding Flashes of the Obvious. I was reading your post thinking "Yes, why is it that gay men have more sex partners than straight men," and suddenly it came to me: straight men have to get over women's many defenses. They have to woo us, or at least seduce us, fool us, or get us drunk. The old joke: women need a reason to have sex, men just need a place.
So you get the gay community, where NO ONE, presumably, is holding out for flowers and candlelight... just a bunch of guys looking for a place... the male sex drive remains the same whether it's aimed at a woman or a man...
Sorry, folks, I'm just musing out loud and marveling that this has never occurred to me, that the gay male community would necessarily be promiscuous because it's all men.
Not to cast aspersions on all men, of course. But, well... there you have it.
There's another very important part. Women demand fealty; a monogamous relationship. Men acquiesce. Or, at least, most do.