I’m sympathetic to his argument that if it’s good code then it’s good code and if it isn’t actually useful or has flaws those are already reasons to reject it.

And since you can’t actually know for sure how much of a piece of code (or commit message) was written by AI you don’t really have a choice, do you? As time goes on and more people try to learn programming using AI a bunch of them may end up picking up some of its stylistic stuff. And if the submitter uses proper kernel formatting standards, will you be able to tell?