I actually think it's ironic for precisely that reason. Similar to covering music, there is a legal precedent for making books available in public libraries - though most cover artists don't pay the royalties, and in this case this online library is not paying the GP. In the case that GP did in fact pay the fee, I rescind my criticism.

My understanding is that libraries do pay fees to stock books, some of which goes back to the original author. Anna's Archive does not pay anything back to the authors.