They bought each one as a copy. They aren’t taking all copies of all books.
Not sure why I have to explain basic math to you but here we are. Learn math bro.
And get if they are recycling THEIR ONE COPY OF EACH which they no longer use that isn’t illegal nor worth an outrage. That’s how recycling and reducing waste works. Better than hoarding.
Do feel free to go buy a copy and support the author if you’re this passionate to get enraged over what someone does with their own one single copy.