An interesting study of the phenomenon from the 1970s casts some light:

Humphreys found that 54 percent of the men were married and living with their wives. He found 38 percent considered themselves neither bisexual nor homosexual. The men wanted a sexual release that was quick and would not endanger their standing with their family or society. Just 14 percent of the men identified themselves as living-in-the-open homosexuals.

"Most of the people who do these things are actually heterosexual," said Joel Jackson, youth advocacy coordinator for Project Ark, a St. Louis-based AIDS outreach group.

I'm not sure I buy that. I'll bet many of them are closeted, conflicted or gay-and-married-to-a-woman. They say they're hetero, sure. But the Onion had the best riposte to that. The simple truth is that men are horny creatures. If they can get quick and easy no-strings sex that satisfies them, they often will. That goes for straights as well as gays, which is why you tend not to hear of stings of lesbians hooking up in public places. But gay men have an advantage over straight men: a lot of willing partners who won't call you the next day and won't even ask your name. If straight guys had this option, you think they'd refrain? Please. That's why women and social norms are the main historic constraints on male sexuality. And why, with gay men or straight men who don't care who's blowing them, the social norms, like civil marriage, are even more important. But the Christianist right wants no social acceptance of gay relationships and no random sex either. I'd say they need to pick one or the other, wouldn't you? Or is that too much human reality for them to cope with?