However, Anne Rice does not put her stuff into the public domain. In fact, she gives explicit restrictions on what would otherwise be part of fair use (Anne Rice fanfiction is not allowed, for instance).
If you put something into the public domain, it is public domain. I may not be able to credit a book full of dongs to Hoopla, but I can probably do it to Lewis Carrol because he's been dead for over a century and doesn't really give a fuck. Copyright law is not deeply intertwingled with restrictions on libel in this case.