Children are sent to school for an education, not to be kept from becoming educated because of the prejudices of parents. If a parent objects to a book, they have the right to say they don't want their own child to read it, but they should not have the power the keep that book from other people's children! When I was teaching, I cannot recall one single instance of anyone wanting a book taken from a reading list, etc. where the reason made any sense except that we had an ignorant parent with preconceived notions.
For instance, I recall a parent objecting quite vociferously to Bernard Malamud's "The Fixer," insisting that she didn't want her daughter reading about "drug dealers." When she finally caught a breath, I asked her the big question: had she ever read the book? Of course not, she screamed, she would never read such a book! I calmly told her that the book actually took place in a Russian prison and had nothing to do with drugs. She just stared at me (how difficult it is to find you are screaming with no sense of reality). I've never yet met anyone who objected to a book and in fact had read the book.
And, by the way, what if the book had been about drug dealers? The real issue is not the subject matter so much as whether it was a good enough book. Does it have literary merit or is it a piece of junk?
Looking at banned books from the historical perspective, to be banned puts a book in excellent company for the most part: Huckleberry Finn, Lady Chatterley, Of Mice and Men, Catcher in the Rye and Jude the Obscure are just a few of the novels regularly banned throughout the years from libraries and school lists.
My suggestion is that anyone who wants to ban a book should be instructed that they must first read the book and then present a written report on it, pointing out why no one else should have free access to reading that book. Would certainly cut down on book banning.