Maybe somebody at the library has a strange and over-reactive sense of what sorts of words are offensive. After all, nothing bad ever happens in the world -- ever -- and if we completely remove all references to bad things, the bad things go away, right?
Maybe there's some kind of weird story behind some of the oddball censored words. I wouldn't be surprised at someone getting enraged over random things and harassing the library until they just gave in and censored it. "Don't you know that I find roller skates offensive??? I demand that you remove all references to them!!!"
Maybe a bored librarian/intern/whomever got access to whatever software it is that determines which words are censored, and tossed a few completely random ones in just for giggles.
I think that I like the last explanation best, because it's the funniest...