The reason is clear -- like it or not, as Americans we're very comfortable with images of graphic violence and fake sex. Hostel, a wild and effectively grisly thriller (if you're into that sort of thing) firmly positions its violence and raunchiness squarely through the eyes of a few aggressive, (intentionally) obnoxious college yanks abroad. By seeing this fantasy sex through the eyes of young straight guys, it's not real, it's a hyped-up extrapolation on the femme fatale, in this case, a luscious and willing babe who will f*** you whenever you please, but might also kill you before morning. Classic take on horny men blindsided by too-smart, predatory, opportunistic women. And the women, particularly Barbara Nedeljakova, are fabulous. The peek-a-boo sex here is not real and has no emotional connotations or complications, and this makes it palatable to its horny fan-boy target audience. However, I will defend the violence because this is Grand Guignol of a high order, Roth knows what horror films can and should do and Hostel's extreme cruelty is inspired and dark as pitch. When the film's grueling third act arrives, the torture chamber antics are very, very real, and far away from any sort of "boo" thriller that trots out manufactured chases, red herrings and tension relieving laughs. It's horror, folks, the real deal.
Brokeback Mountain, by contrast, deals in the stock and trade of real, adult feelings--the stuff which invites discomfort here in good old America, particularly from two masculine guys feeling those things together, without the benefit of hijinks, come hither chicks or blood, all diffusers that Hostel employs beautifully. There are no such filters in Brokeback Mountain, just feelings.
rt