This is a gay thing? Funny, I don't see any mention of women meeting up and having sex in those stories, which would be true if homosexuals were more likely to do this.
If there is a difference, I'd suggest it's more that *men* (or a small but significant minority of them, at least) are morely likely to do sex with a random stranger. A consequence of it only being men is that it ends up being homosexual - I'm sure there are *plenty* of men who would love to meet up in public and have sex with a random female stranger, but let's face it, doing so is a lot harder;)
Another thing to note is that it says many of these men are family men. I'd suggest that these are men who may not be out about being gay or bi. Since they have a wife and maybe kids, they can't exactly bring a guy over, so they look for some easy public place. The reverse situation of a person in a gay relationship being in the closet about being straight or bi seems a lot less likely to me, given the way that people are brought up to assume that being straight is the normal standard default way to be.
And there are plenty of straight couples having sex in public places. But I wouldn't claim that the straight scene (whatever that is) is misbehaving.
