I think the Grapes of Wrath is still banned in some Oklahoma public schools simply because it painted a realistic picture of OK during the dust bowl and depression days, and OK didn't like that reality.

In Texas, I'm surprised any book that mentions science isn't banned. Or for that matter, any book that dares to question fundamentalist Christian beliefs. They are so closed minded here. You would laugh or cry if you knew the crap they taught us in school in the 1960s and 1970s that they claimed was history! It was mostly highly embellished legend, and far from historical. Kind of like the Faux History Channel on TV.