To be honest, I'd be MUCH less against this practice if this shredding at the very least included saving the original scans at at least 300 dpi for everyone to access, freely.
Ideally, they wouldn't cut them by the spine, but even giving the despined ones to an archive/library would be just above the unpermissible line.
Despining, scanning and public access archiving is borderline permissible.
Yeah, sure. Everyone throwing out old books is knowledgeable enough to know and willing enough to check that the book they're throwing isn't rare or important.
You'd think people would check on the off chance it's worth a bunch but you'd be surprised.