Even if a text completion engine like GPT had any responsibility for truthfulness, which it doesn't, there's a disclaimer right there on the page you have to agree to in order to use it. Trying to pin blame on ChatGPT for defamation is like trying to sue Snapchat because its filter put cat ears on you when you in fact do not wear cat ears.
So you are okay with my new website that randomly makes false claims about you, as long as I have a disclaimer and don't actually understand how my software works?
Sure thing, go crazy. Nor do I care if you cast me as a villain in your D&D campaign or a racist pedophile in your novel. I don't care about made-up nonsense when there's a sign there that says it's made-up nonsense. All responsibility and liability is with the human being who repeats the nonsense as fact.