Earlier quoted context omitted.
That's not really how it works. That'd be like saying all oil paintings are in the public domain because paintbrushes can't hold copyright. The copyright goes to the person triggering the generation of the content similar to how if you use blur tool in photoshop you don't suddenly lose copyright.
Maybe that will be the case in future after a court decides so, but at present AI content does not get copyright protection. https://www.klgates.com/Federal-Court-Rules-Work-Generated-b...
That's not what the article says.
The article says that an AI cannot hold copyright. This is not the same as AI content cannot be copyrighted. As I said before, a paintbrush cannot hold copyright; that does not mean a painter who used a paintbrush can't hold the copyright to the work.
This is basically the same thing as when that guy left a camera out and PETA tried to get the monkey that took the photo to be assigned copyright [1]. PETA failed; animals cannot hold copyright and the guy that left his camera out can.
[1]: https://arstechnica.com/tech-policy/2016/01/judge-says-monke...