No, because taxpayers are still paying for the shelf space. It’s their building and they get to decide what’s in it. Now, if private groups want to rent space and make certain books available there, they’re welcome to do that.
Wait, but both of those are censorship of a form; Apple is just allowed to censor whatever it wants.
Taken to the extreme, should a library be allowed to stock only books that promote the political party of whoever won the latest election?
Obviously decisions for shelf space have to be made. If those decisions for shelf space are made solely by the government's dislike of the material, though, that feels pretty obviously like government censorship to me.