Destruction of books is normal and totally OK. Publishing houses do it daily in the thousands. When you own something, you can choose how to dispose of it. Come back when you have the title of actually valuable rare books that were bought and destroyed. The 404 article was not well researched in this regard.

The emotional reaction we're conditioned to have hearkens back to 1940s Germany, where the goal was to have people burn all the copies of existing works. But this is not that. They are going for "one of each book" so they have a comprehensive corpus of works to train from. They are willing to buy books to obtain this corpus. It sounds like the system working exactly as intended, with even the book sellers selling these books saying they are "dead inventory".

There's a time to be breathless about "destroying all of humanity's knowledge", but let's wait until it's actually happening.

Again, I'm am very anxious for anyone to come forward with credible information about any valuable/rare/irreplaceable book that was destroyed in this process. So far zero people have been able to do this, probably because they are buying the books in bulk and want to obtain them as cheaply as possible. Book sellers will know the value of any actually rare/valuable books, and would charge accordingly, which would be pointless for e.g. Amazon to pay. They don't need some crazy first edition, they just need some copy to digitize. The incentives just don't add up to "Amazon is buying priceless art and burning it!" the way the narrative suggests.