But if you simply copied the unique works and stored them, nobody would care. If you then tried to turn around and sell the copies, well, the artist is probably dead anyway and the art is probably public domain, but if not, then yeah it'd be copyright infringement.
If you only copied tiny parts of the art though, then fair use examinations in a court might come into play. It just depends on whether they decide to sue you, like NYT did in this case, while millions of others did not (or just didn't have the resources to).
They are copied. If I can say something like “make a picture of xyz in the style of Greg rutkowski” and it does so, then it’s a copy. It’s not analogous to a human because a human cannot reproduce things like a machine can. And if someone did copy someone artwork and try to sell it, then yes that would be theft. The logic doesn’t change just because it’s a machine doing it.
But if you simply copied the unique works and stored them, nobody would care. If you then tried to turn around and sell the copies, well, the artist is probably dead anyway and the art is probably public domain, but if not, then yeah it'd be copyright infringement.
If you only copied tiny parts of the art though, then fair use examinations in a court might come into play. It just depends on whether they decide to sue you, like NYT did in this case, while millions of others did not (or just didn't have the resources to).