The argument of copyright is that 'published' information is
not public. It is still owned by its creator (or more often by one of the corporations that employ them), you just get a very limited license to do certain things with it, like reading it and maybe creating personal backups, but not other things, such as sharing it with others, either for free or as part of a commercial venture.
This distinction between owning and licensing information didn't use to be necessary in the publisher's business model for popular culture, because the cost (and, equally importantly, the profit margin) of distribution was significant: authors made and continue to make far less than their publishers, with rare exceptions.
The cost of distribution of digital information is so low that consumers will do it for free (BitTorrent). And since the power of publishers primarily derives from their ability to distribute copies, that is what they attempt to preserve, even though they do a lot of other things that continue to be valuable in today's digital world, like financing and advertising. This (not entirely irrational) attempt to preserve a dated business model is in turn perceived by consumers as a clampdown on their rights, leading to a backlash to the established publishing industry and enabling the (so far limited) success of new services like Spotify and Netflix, which don't have to take into account any reconceived notions of what their business is. People associate licensing an ebook with buying a treebook, but they tend to associate streaming with borrowing a book in the library.