Perhaps, but by not even buying the book they’ve conceded the point. IMO copyright law does not control what you can do with a book once you’ve bought a licens

Perhaps, but by not even buying the book they’ve conceded the point. IMO copyright law does not control what you can do with a book once you’ve bought a license, except for reproduction. It’s arguable that LLMs engage in illegal distribution, but that’s a totally different question from whether simple training is illegal even if the model is never made available to anyone.