Ignoring the GPT part of the problem all together, claiming someone to be the most incompetent programmer in the world would probably fail [2] for being understood as a statement of opinion rather than fact, possibly [3] if there was any basis for the claim whatsoever, likely [4] because the named individual would have to prove they were damaged somehow (maybe not if it led to them being denied employment or something), and [5] because the average reader would almost certainly understand it as hyperbole.
Reintroducing the GPT part, assuming the defendant is OpenAI for output of GPT, I would also argue a failure on point [1]. OpenAI doesn't release to the general public the output of the GPT program.
Judges are liable to be old, not very hip to technology, and incredibly suspicious of any argument that would allow someone to opt out of traditional culpability by adding with an AI to the end of a description of traditional wrong doing.
Isn't compiler output copyrightable?
Not by the compiler vendor.
if a pilot gave the airliner controls to a dog, we wouldn't blame the dog or its parents for crashing the plane
For libel against someone who is not a public figure the defendant does not have to have known their statements were false. The plaintiff just needs to prove the defendant was negligent.
1. knowing it was false
2. publication
3. damages
I am not a lawyer, this is not legal advice.