Whether or not the use is commercial is certainly one of the considerations, but it's not the most significant one generally. There certainly can be specific cases where it's very significant, of course.

But what I was arguing was that a use is not "fair use" merely because it's noncommercial in nature. I cannot make copies of movies and give them away on the street for free and successfully claim "fair use".

Agreed.

Because anyone that is familiar with fair use knows that the purpose prong and the commerciality aspect of it is not one of the more important prongs of the fair use analysis, whereas transformation is. Transformation adjusts what is a purpose that falls under fair use. Did you read Warhol??

Yes. Warhol is an example where the commercial nature of the secondary use was the deciding factor in its failure to pass the purpose prong.

  > In sum, if an original work and secondary use share the same or highly similar purposes, and the secondary use is commercial, the first fair use factor is likely to weigh against fair use, absent some other justification for copying.

(P4). It’s very likely that a noncommercial secondary use would have passed under the reasoning in Warhol. I don’t understand the point you’re trying to make.

Read what you quoted - the commerciality of the use comes after whether or not the use was transformational. That's the entire of point Warhol - when the use is not transformational, there is very little space for a commercial fair use.

Your parent is more right than you.

Weird Al has made a fantastic living copying music while only changing lyrics. He makes very heavy use of the satire plank of Fair Use.

The “commercial” test is only part of the decision criteria for Fair Use.

I'm pretty sure Weird Al is actually using compulsory licensing in music and just paying the required royalties to the songwriters. Anyone can cover any published song, you just have to pay the royalties when you do.

He doesn't actually make very heavy use of the satire plank of fair use. He credits the original artists. From his own website

"Does Al get permission to do his parodies?

Al does get permission from the original writers of the songs that he parodies. While the law supports his ability to parody without permission, he feels it’s important to maintain the relationships that he’s built with artists and writers over the years. Plus, Al wants to make sure that he gets his songwriter credit (as writer of new lyrics) as well as his rightful share of the royalties."

The fact that he could rely on fair use is separate from whether he as an artist does rely on fair use.

Weird Al makes a point of getting permission even though he views his satirical works as fair use.

The "commercial" test is only a part if the criteria and not necessary, but to say it has little impact is clearly false.

Always great to see people point out Weird Al, cause he's the shining beacon of an example of what OpenAI et al. should be doing. He explicitly gets permission from the original authors before doing any of his parodies, and he's even been turned down a few times as well, famously Prince rejected him a bunch of times and he subsequently has never made a Prince parody.

Not only does he get permission from the original authors, he also pays royalties to the authors despite legally not having to do so.