From their perspective, it's training data that their competitors don't have. If they make it available, they fill in their moat.
I love how sci-fi authors like Ray Bradbury toyed around with a similar issue but then got it so wildly wrong.
More importantly: Once Anthropic is gone, all knowlege is lost.
They cannot scan the books then resell them or donate them under current US copyright law. It’s not clear to me that they could warehouse them if they wanted. In the recent Bartz v Anthropic case the judge ruled this destruction as legal, saying
> The print original was destroyed. One replaced the other.
So that there was still only one “copy” of the book. This is in compliance with the DMCA. You can make a personal digital copy of a work but then you cannot resell the hard copy and keep the digital one. Same principle applies here.