I've wondered, too, if in trying to understand I was over-thinking or over-analyzing, and if it isn't simply the flip side of the stereotypical straight male fascination with "girl-on-girl action." Haven't wanted to go there, though, because it seemed, well, stereotypical, condescending, and possibly even insulting to women. 
No, it's a valid question. And if you can't ask it here, where CAN you ask it?
I'm no expert (as Scott might say, this is speculative rather than authoritative
), but I think they're different, and here's why. The stereotypical straight male fascination with GOG action strikes me as a bit more exploitative. To me, it seems as if the men like the idea of the women putting on a show
for their benefit. As far as I can tell, straight men are not as fascinated by watching two lesbians, i.e., women who have no sexual interest in men, as they are by two women -- in many cases, straight women -- who create an implied threesome with the voyeuristic viewer. For instance, those girls who make out in "Girls Gone Gone Wild" videos seem to be straight women who wouldn't ordinarily be making out but who do it for the sake of being filmed for a product that will be marketed to straight men (crass and tasteless straight men, I might add, along with some other adjectives, but that's a different story). And that appears to me to be what straight men find most appealing. (If anyone can correct me on this, feel free -- I've never actually discussed this with any straight man who admits to finding this hot, so these are just assumptions based on cultural observation.)
But women who like slash seem to be fine with the idea that the men are there for each other. Oh, some might fantasize about being there in the tent with Jack and Ennis, for example, but that's not essential to enjoying the scene.
But what they have in common, I think, is an equation that applies to straight people of either gender, which is: Attractive people of opposite sex + sex X 2 = hot.
Does that make sense and sound right?
