> I thought that was because only humans and other legal persons can legally author things, not because of anything subtler about the nature of LLMs.

It very explicitly was and made a point of noting that it was not addressing anything about whether and when a human author could hold a copyright on a work authored using AI.

Correct, as usual, everyone interprets that case as 'OMG animals/AI created work is uncopyrightable!1!' but in reality it's just that animals/AIs cannot hold copyright. Whether a human using an AI can copyright the resulting work is still up in the air.

In the monkey-photo case, didn't the journalist attempt to assert copyright on the photo the monkey took with his camera, but was denied?