>So the better analogy is if you rent a Xerox copier to copy something by Warhol

It isn't.

One analogy in that case would be going to a FedEx copy center and asking the technician to produce a bunch of copies of something.

They absolve themselves of liability by having you sign a waiver certifying that you have complete rights to the data that serves as input to the machine.

In case of LLMs, that includes the entire training set.