I grew up in the 50s and 60s, and I read between two and four books a day. I never read books by Roald Dahl (I am not American), but I did read Enid Blyton. I switched to the classics (18th, 19th, and early 20th centuries) very soon, though, and these books are full of ideas we don't accept today.

None of this made me a racist or a mean person. So I'm confused as to why anyone would think that reading books written in another time or place will make someone take on ideas that are unethical. If anything, those works gave me a unique ethical foundation which I still practice today.