Why shouldn't it be in the school library? It's a book from a movie lots of teenagers have seen.
The content is not appropriate for adults to be providing for children to read. Period. If you don't understand that, you have my sympothy.
What was the movie rated?
cyborg, I think the problem is that the book is part of some approved curriculum (which I take to be either REQUIRED reading, or on a list a student MUST choose from as part of an assignment) not just that it is in the library.
At least that is my take on it.