It is not banned when you do not wish to have it in school libraries. Especially elementary and middle school libraries.
A book not being available in a public library is a bit closer to the concept of banning so let's talk about Abigail Sheere's book "Irreversible Damage" and why the American Library Association banned it..... wait.... where are you going?
Guess they had an appointment elsewhere.
The latter is on a step along the path toward criminalizing hate speech. Someone has to protect children of tender years who lack discernment but paternalism toward adults is censorship.

BTTT