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”.
The practical difference is that, in one case, the taxpayers collectively decide what's appropriate for their children and what is not. In the other case, a single (or a few) individuals decide what is appropriate for all the taxpayers children.
I don't understand why some people think it's better to ignore the wishes of the voters.