Purely generated AI content can't be copyrighted.
However, mix some human effort in, the combined work can be copyrighted. In theory if you can prove a specific thing is purely AI output, it is fair game. Good luck doing so with proof.
The cases cited in this argument all had the would be rights holder stating flat out it was untouched by human hands. Once they did anything to it, the result would be "transformative" and the AI ness won't count.
Also in this case, the games being decompiled were pre LLM. An LLM clone doesn't spare the clone of legal issues. A company tried this argument that the knock off legal papers were AI and this fair game and they lost. When Getty sued, the counter argument was that output could be infringing, but it would be the responsibility of the operator.
Conveniently for the rich people, they have rights to make knockoff machines by ingesting everything without permission, but copyright of course still counts for their purposes.