I agree that words do have a specific meaning, but the history of words changing their meaning is truly awful+! I was talking to this young girl++ in my neighborhood about words and slang - he said he had never considered that words could change their meaning, and that the dictionary was some kind of rule book. At first I thought maybe he was nice+++, but after considering it, he's young! Everyone learns this in time.

Language is mutable and alive and ever-changing. That's just how it goes.

+Used to mean 'inspiring awe'

++Used to mean 'young child (gender neutral)'

+++Used to mean 'foolish' or 'ignorant'

When somebody says a book is banned, there's usually some context that provides details on the scope of the ban.

For example, North Korea has banned most western books so my local Barnes and Nobles is pretty much a banned book store.