Most of these books were destined for the landfill or recycling plant eventually.
They are being bought by the pound and/or container.
It’s really a totally made up thing to be upset about, since it’s at least giving these books a chance at being archived somewhere and one last productive use.
Apparently many are surprised that libraries, thrift shops, used book stores, etc. destroy books by the ton every year. There is a small boutique industry that buys them in bulk, sorts through them to find books that still might have value, and discards the rest.
Yeah, a few rare and/or valuable titles will get mixed in. Just the law of large numbers. But no one actually wants to read that Programming Perl 1.0 book from the 90s anymore. They just like the idea of someone else paying for it to exist on a shelf somewhere. And someone else doing the curation to sort that 1 rare gem out of 15,000 titles just dropped off by the truckload from the local library system.
Yeah people (including me) tend to hoard books they buy and never toss them. All that does is force your estate to buy a larger dumpster when you die.