I look at it this way: if I've taught my kids right from wrong from the very beginning, a book is not going to CHANGE HIM. Nor is a cartoon show, or anything else. Then again, if someone lets their children do anything they want, unsupervised, you may get the exact opposite. I read books all the time...fiction, non-fiction, etc. I read about murder, mystery, romance, government, all the time. I am not a murderer, a PI; I don't have a lover on the side and I don't work for the CIA, either.
My son read the Harry Potter books, and I can tell you right now that he's not in his room cooking up some evil plans to poison us all, nor is he stealing from anyone.
Santa Claus isn't real either, should I tell him that?