Whoever operates the LLM, in this case OpenAI, engaged in copyright infringement through the unauthorized modification, reproduction and distribution of content to you.

The person doing the requesting did.

That's not how interactive computer services work.

> sure, but if I use an LLM to write a novel/article, I can be sued in civil court not the LLM

That's function of the legal system, not of the technology. If tomorrow someone made a perfect dolphin-Esperanto translator and proved Dolphins were as smart as humans, you still can't sue a dolphin until the legal system says so.

Wouldn't you find out by suing the dolphin and seeing if it holds up in court?

Not if you were smart, unless you have some sort of solid argument for why the established case law about this sort of thing is faulty.

There is established case law? For a talking dolphin?