It sounds like it is about the information in the books. The titles they're looking for are all nonfiction. Not everything is on the internet, and just because it's a few years old doesn't mean it's outdated.
Speaking from experience, the information density of published books is a lot higher than most internet text. It's very high quality training data.
The goal here is to have all human knowledge in a single file, which is pretty neat IMO.
The internet basically never delivered on the promise of replacing textbooks or even education as a whole. Wikipedia sucks on many topics, has insane internal politics, and is a tertiary source by design (redigesting blogs and books), whereas textbooks are generally secondary.
Booksellers noticed a huge uptick in non-fiction purchases, that is not the same thing as them not targeting fiction at all.
Edit: Actually, I have real evidence, the Bartz in "Bartz v Anthropic" is Andrea Bartz, a novelist, and the complaint specifically lists four of her novels as infringed works.
I see. So it is much less about 150 year old fiction books, but more about 1980s science literature that was only ever printed five times. That makes a lot more sense than what the public debate seems to be about.
Speaking from experience, the information density of published books is a lot higher than most internet text. It's very high quality training data.
The goal here is to have all human knowledge in a single file, which is pretty neat IMO.