The Ska Librarian aka Dan Cherubin has written an excellent article on Banned Books Week for Counterpoise.
Banned Books Week does a reverse spin by focusing solely on the library as a children’s space, complete with requisite put-upon spinster. With Banned Books Week, ALA has created a safe space for generating a manageable and marketable taboo. It could be that with all the actual fighting librarians do over real issues, they wanted something that they could profess to win repeatedly. If one creates one�s own taboo, one usually knows the easiest way to transgress it.