It makes you wonder why Knuth bothered with an outdated ChatGPT version? He couldn't find someone with access to GPT-4?
Maybe he has seen similar claims before and is too old and dumb to not realize how world changing this is.
My take away is that he views this as another tool we are still figuring out how to use.
My advice to you is to never dismiss anyone's opinion just for being old. And I hope you lose your ingrained ageism before you become old yourself, otherwise you'll find old age intolerable.