I'd remove it and whether it's censorship or not doesn't really apply because it's a free library and I can take whatever book I want from it and if I choose to burn it or shred it for use in a hamster cage than I can. I'll censor those who want to spread hateful or pornographic material in my neighborhood if it's left in a public book box like that. But personal censorship just means like, yknow doing that or tearing down flyers you don't want around etc. I guess if a government were to do it it would count as censorship but they'd probably just get rid of the whole free library box under some zoning law or whatever.

This is a really reddit question. Part of my free speech is being able to counter other people's speech and a way of doing that is physically removing it from public space.