> You may be conflating “libraries” with “school libraries,”
For the purpose of this discussion, there is zero difference, unless you can articulate one that matters. Feel free to mentally prefix any mention of "library" with "school" if you like.
School libraries are state institutions under the control of various Boards of Education. As state institutions their rules and policies can be set by statute or Board policy. It has nothing to do with freedom of speech. English teachers likewise must focus on teaching English at work, but this is not a restriction on their freedom of speech.
(That said, I am opposed to political restrictions on school library books. It is still not a free speech issue.)
For the purpose of this discussion, there is zero difference, unless you can articulate one that matters. Feel free to mentally prefix any mention of "library" with "school" if you like.