Is that an argument against the quality, saying that AI cannot (or some weaker claim like that it does not usually) produce "art"? Else, is it an argument of provenance, akin to how copyright currently works, where the same visual representation is "art" if a human makes it and is not "art" if an AI makes it?

When pedantry pays the bills this will be a helpful mindset.

Stop trying to impose your narrow-minded definition of art onto other people. If you disagree, that's fine, but you've lost my respect the moment you tell someone else that their definition of art is wrong.

I don’t see this as a claim that the AI is doing art. He’s just saying, that the art can be created at low incremental cost.

Like, if we were in a world where only pens existed, and somebody was pitching the pencil, they could say “With a pencil if you want 2x or 5x or 10x as many edits, it's an incremental cost, you can explore ideas and make changes without throwing the whole drawing away.”