I think the reason I don't consider Kids to be gross is that although there is promiscuity and unprotected sex, there is nothing "unnatural" or masochistic, as for example in Salo. Sex by its nature is not disgusting.
Gaz; It's not the sex but the ignorant & prejudice ATTITUDES that I find discusting in Kids.. (& in people in general..) Can't comment on Salo 'cos haven't seen it yet but doubt it can be groser than Kids..;-)
I ought to take back what I said about there being no "unnatural" sexual activity in Kids, as of course there is a rape at the end of the film. I still wouldn't call it gross though - it clearly depends on your personal definition of the word.