I think it comes from a place of bitterness. We hate watching beautiful people do what beautiful people do.
As someone who was entirely shut out of the whole college debauchery scene, I had to overcome my own feelings of bitterness in order to keep watching. I'm glad I did. This movie was highly rewarding.
In a Facebook/Twitter world, people like to "sound off" about whatever new thing they experience. But most people are only as nuanced about their tastes to be able to say they either loved or hated something. This isn't an easy movie to love, and to be fair it's somewhere in the middle, but I'm not surprised that on "sound off" outlets like IMDB, people are showing up to broadcast their hate. It's not as exciting or empowering to say that they kind of liked something or weren't sure what they thought or that it wasn't what they expected. Most people are uncomfortable facing challenges, ambiguity, or surprises, and the easiest reaction is to dislike something different. Like with any ambitious movie, it will be more fair to give this some time to worm its way through your brain rather than instantly react.
shareIt's not as exciting or empowering to say that they kind of liked something