The other question, which I think is more topical to this lawsuit, is whether the company that trains and publishes the model itself is infringing, given they're making available something that is able to reproduce near-verbatim copyrighted works, even if they themselves have not directly asked the model to reproduce them.
I certainly don't have the answers, but I also don't think that simplistic arguments that the cat is already out of the bag or that AIs are analogous to humans learning from books are especially helpful, so I think it's valid and useful for these kinds of questions to be given careful legal consideration.