Someone still decides the book is not gonna be there, mostly for ideological reasons.
I guess if you agree with those reasons, it’s “curation”, if you don’t, it’s “banning”.
Curation is part of the job for librarians, and it's a specialized skill. I don't have to agree with an ideology to accept what they do is curation - a Librarian in a Taliban library still curates their collection regardless of my endorsement of Sharia. If they are instructed by Kabul to remove specific texts, then it's a ban.
Someone decides what music gets played on radio and what the TV lineup looks like and calling that selection "banning" is reaching IMO . When the legislature is coming up with a blacklist, then it's blatantly "banning" to me