A little of both, I think. People like taking the show apart, but I think they find it a little intimidating to write. It's hard to attempt case-fic without serious, serious research, and the risk of getting it wrong is high. Under those circumstances, I think people default to slash. If people are in a relationship, it's easier to get them to talk about their feelings (in fic, at least) or you go straight for the porn.

I might be selling them short, of course, but it's such a well-written show that attempting to really mimic it (the way you can with Atlantis) is very, very hard.