It doesn’t matter what he argued. What matters is the judge’s decision, and that was about whether AI generated material is copyrightable in the first place. The judge agreed on a summary judgement based on the Copyright Office’s claims, not the plaintiff’s claims. That is legal precedent.

Even the article you just linked to bears the headline:

U.S. District Court Rules That AI-Generated Artwork Is Not Eligible for Copyright Registration

It even goes on to say:

Because Judge Howell found that "Recent Entrance" was never even eligible for copyright protection, she did not address Dr. Thaler’s work-for-hire argument. The only question relevant to the ruling was whether a work generated autonomously by AI is protectable under the copyright law – to which the court responded with a definitive no.