There’s a big difference between saying “we don’t think Tropic of Cancer is appropriate for high school kids so we’re going to remove it” and “Tropic of Cancer is banned in our schools”.
The “book bans” happening are mostly the former and while I do think they’re mostly stupid, they’re nowhere near what you’d think is happening from headlines. Very little actual banning is occurring.
I do think it's important to think about the fact that school libraries are where kids tend to access a lot of books (there are of course city libraries, but those places are also being targeted). At least my experience was around that. And many libraries will have a request system, so if a kid is like "I want to read this", then libraries are able to often put in a purchase order, and then make that available for other students.
At least based on my own school experiences, I do think that teachers of a certain ... authoritarian bent would be more than happy to make up a stink of books brought in that would be "banned" from the library if a copy circulating were brought to their attention. Power structures in schools are like that. But that's just conjecture.
I think the general point of the "book ban" terminology is that librarians and schools generally had leeway to bring in more or less anything to the library, and that autonomy is being stripped away for very dark reasons. This is the age of the internet, but from my own childhood, if my school and city library suddenly decided to not provide certain kinds of book, I would just not have access to that at all.
All that to say that you're right on the word in some sense, but it feels fitting to me.
The people complaining about banning are being either intentionally alarmist (if they understand what’s going on) or knee-jerk reactionary. It’s the exact same as when the religious people are mad the state mandates we teach evolution.
School districts and states have to select what kids learn, since we have finite time and resources to reach them, in the same way that libraries have to choose which books occupy finite shelf space.
I don’t agree with a lot of the decisions, but people are acting like it’s some right wing fascism every time they remove Henry Miller a library.