There will be many here who see no ethical issue with this type of lending and that is their prerogative. So, without debating the ethics of this type of information sharing, it is clearly of the same type as old services like Napster and The Pirate Bay. As such, authors don't object to libraries as the article asserts, rather they object to what
they view as piracy.
From a creator's perspective you have a site that did not pay for a single copy of your work, yet is willing to share our unlimited numbers of copies of your work. Authors believe this is clearly not how a library functions but rather exactly how piracy sites work.