a great movie - why has it gotten such poor reviews?

After viewing Art School Confidential, I am as perplexed by the critical bashing it has received as I was by the near unanimous praise for such recent mediocrities as United 93, L'Enfant and Thank You For Smoking. According to rottentomatoes.com, Art School Confidential has received 32% positive reviews (2% less than Scary Movie 4 !?!). It's all the more strange when you consider that the creators' previous effort, Ghost World, a film very similar in tone, style, and quality, was critically lauded. While some of the characters in ASC may be overdone (the film student and Broadbent's), it's a hilarious, truthful and even moving film. I'd have to see Ghost World again to determine which is better, but ASC is certainly right up there. I notice that much of the criticism has focused on ASC's supposed misanthropy, yet it seems that Thank You For Smoking was praised for the very same thing. Could it be because TYFS ridicules corporations, politicians and do-gooders, while ASC mocks artists and academia(whom critics identify with)?