When my daughters were in upper elementary school and older we would sometimes play a silly game of trying to think of a reason for any book to be banned.
What could be objectionable about Goldilocks and The Three Bears? Surely, you don't want children reading about a child who enters a house that is not hers, eats their food, breaks their chairs, and generally makes herself at home. What kind of lesson does that teach?
The Cat in the Hat? That classic can't be bad, can it? Let's see--a parent leaves children unattended and they let a total stranger come into the house. At the very least, that is not good parenting, at worst it is a lesson in trickery and ultimately lying to that neglectful parent.
I won't go on with this because you get the idea, I am sure. Can you think of other examples?
Just to get you excited, here are a few of the most challenged books of the 21st century. I think you will find some favorites on the list. Can you understand why some people might object to them?