If they did there is a protected right to carry such materials. These same draconian censorship rules removed Maus, a kids book, from libraries.
If Maus were rated according to TV standards, there's no way it'd get less than TV-14. Unless you think shows rated TV-14 can be kids' shows, I think that disqualifies it as a kids' book.
Are 14 year olds adults?
It was still in the library.