At all the public libraries I've used they only let me checkout something if the total number of copies already checked out is less than the number of copies the library has licenses for. If the number checked out is not under the number of licenses they make me wait until one of the checked out copies is returned.
That's still no different from the content creator's point of view than a non-sale or pirate. The practical limitations of libraries is immaterial to the fact I can view content without paying the creator anything. Carving out some logical exception for content pirates is ludicrous. They're functionally no different than non-customers or library patrons.
The physical limitations of libraries are immaterial. Patrons are non-customers of the content publisher. They're doing the same exact thing pirates are doing, experiencing some piece of content without paying the original publisher. The same thing as if they watched a movie on broadcast TV, listened to the radio, or bought that content second hand.
If you're going to argue against piracy you're also arguing against libraries. The differences between a pirate and a library are mostly statutory.
Wait until the grandparent learns about public libraries. Just havens of content larceny! People "stealing" content left and right!