Consider this: the Da Vinci Code, despite its calumny against the church, was not deemed to be too controversial to turn into a film. There is another book that has attracted the attention of screenwriters, and by most estimates, would be a natural to turn into a screenplay: John Kennedy Toole’s "The Confederacy of Dunces". What’s interesting is that despite the interest, a film adaptation continues to languish – the latest casualty was a version starring Will Farrell that was scheduled to be released in 2005, but was stopped mid-filming.
My guess as for why The Confederacy of Dunces will never be filmed is that the book is chock full of characters who, at first glance, appear to be stereotypical. To appease the hypersensitivity of American culture to ethnic stereotypes, these would have to be eliminated entirely. This would inevitably dull the humor of the adaptation or even change the essence of the book altogether. Either way, it’s not a recipe for success.
So, my point is this: It appears that, as far as Hollywood is concerned, sinister stereotyping and slander against the Church is OK. Having characters that are based in ethnic stereotypes is not OK, even if the stereotypes are ultimately transcended.