I think Hollywood gets away with it, because it's gore/horror/torture. In movies such as Hostel, There's no real sexual interaction involved between the perpetrator, and the victim. (Intercourse, Forced rape, Necrophilia etc..) So it's not really a porn flick, IMO. It falls more into the gore/horror genre. If forced rape, or other sexual activities were involved, then it would probably cross that invisible line of community standards.