Frankly, this sounds like you're overreacting. No one is preventing these parents from getting these books for their kids on their own. No one has "banned" these books. They simply decided they were not appropriate for the school library.

Also, schoolboards all over the world select material that they consider age appropriate.

Also, I'd like a more comprehensive list of what, exactly, was banned. I suspect, for your examples, you simply chose the two tamest books you could find.