Someone stuck some gay porn in my romance!

So, this particular entry was inspired by the woman who cuts my hair. She was talking about how Bareback, sorry, Brokeback mountain was so hot etc. Now, I know that there are some women out there who totally dig on guy on guy porn. But, when I started asking around amongst my femail friends I found myself very very suprized! Apparently, most women haven't seen much of the guy on guy variety, but what they have been watching is girl on girl porn. In some cases women seemed to prefer girl on girl to even regular porn. Now, as a guy I imagine that probably about 90% of men would choose girl on girl porn over most anything else in the universe. But, and here is the crucial question:

Why isn't the opposite true?

Why don't chicks dig on the guy on guy? Asking around, I've gotten a bunch of different answers (from women):

1) Chicks are just more beautiful physically, and are more enjoyable to watch. Far more erotic.
2) Women with women is more acceptable socially because they aren't doing anything a man and a woman wouldn't do. Whereas men with men usually means anal sex, and lots of people find that disgusting. Or at least not very erotic.
3) For women, watching gay guys means that girls can just see their way out, while watching women implies that they are free to join. Which, at least on the surface, is a lot more appealing to think about.

Now, all of these are pretty good reasons in my book, and not being a woman I don't suppose I'll ever get a real idea of why chicks like chicks. But, it should be noted, plenty of women I asked thought that Brokeback mountain was hot, which makes me wonder . . .