Having grown up in a fundamentalist Christian household that was on the cutting edge of the Jesus was a Republican movement, I may be able to offer insight into why conservatives, and especially fundamentalist Christians, are in favor of banning books. They'll never say this out loud, but because they believe a host of things without evidence, all on the translated words of a deity they can't see, they think that everyone arrives at their beliefs the same way. Books and authority figures give them their beliefs, so if someone reads the wrong words or interacts with the wrong person, they're likely to take on the false beliefs found in these books and heard from these "others." Words are the virus that infected their mind, and reason, if it's appealed to at all, exists solely to prove existing beliefs true; It isn't a tool for arriving at the truth.
Having grown up in a fundamentalist Christian household that was on the cutting edge of the Jesus was a Republican movement, I may be able to offer insight into why conservatives, and especially fundamentalist Christians, are in favor of banning books. They'll never say this out loud, but because they believe a host of things without evidence, all on the translated words of a deity they can't see, they think that everyone arrives at their beliefs the same way. Books and authority figures give them their beliefs, so if someone reads the wrong words or interacts with the wrong person, they're likely to take on the false beliefs found in these books and heard from these "others." Words are the virus that infected their mind, and reason, if it's appealed to at all, exists solely to prove existing beliefs true; It isn't a tool for arriving at the truth.