Prisons Banning Books
The state of Oregon’s prisons have banned a large number of innocuous books which teach programming-related topics, under the guise that learning programming and related topics constitutes a security risk.
Other states are mentioned as doing the same in the above; (n.b. a quick moment of searching didn’t turn up an immediate article on another state, but see below, I likely just didn’t look hard enough and likely can fill this in later with other examples).
(The Oregon Department of Corrections is the state entity, not a for-profit prison.)
Other questionably-banned book categories are discussed briefly here and here.