Well, yes, that's the thing, right? The best way to censor something is to disappear it without anyone noticing. The OP asserts that censorship is something that we can inherently discern and that the announcement of the book-banning proves it. No it doesn't. If the library were to just remove the book, people would just read some other book or do something else.

I'm not philosophically opposed to the OP, I'm just pointing out that the most dangerous censorship is the kind you aren't aware of