Human brains are still the main legal agents in play. LLMs are just a computer programs used by humans.
Suppose I research for a book that I'm writing - it doesn't matter whether I type it on a Mac, PC, or typewriter. It doesn't matter if I use the internet or the library. It doesn't matter if I use an AI powered voice-to-text keyboard or an AI assistant.
If I release a book that has a chapter which was blatantly copied from another book, I might be sued under copyright law. That doesn't mean that we should lock me out of the library, or prevent my tools from working there.
I see two separate issues, the one you describe which is maybe slightly more clear cut: if a person uses an AI trained on copyrighted works as a tool to create and publish their own works, they are responsible if those resulting works infringe.
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.
Suppose I research for a book that I'm writing - it doesn't matter whether I type it on a Mac, PC, or typewriter. It doesn't matter if I use the internet or the library. It doesn't matter if I use an AI powered voice-to-text keyboard or an AI assistant.
If I release a book that has a chapter which was blatantly copied from another book, I might be sued under copyright law. That doesn't mean that we should lock me out of the library, or prevent my tools from working there.