Libraries aren't unethical, because they're just letting you borrow stock of books. There's practical limits on how it scales, and any impatient users might just buy the book. Once you can infinitely duplicate a work, it's not borrowing.
So what? I think, if you read a good book, learn something or are well-entertained, it's a positive externality, so there is no problem with people doing it for free.
The only real issue with IP piracy is when someone gets money by copying the works. Which were originally the cases copyright tried to prevent.
Maybe you can clarify why you see people doing these things for free a problem, when there is a net benefit to society and also you.
When people around me ask about how to "get into reading" I tell them to just find stuff they like online (via AA) or at the library and go from there. If you don't pay initially you don't feel as bad about trying things that may be "bad" or that you aren't interested in.