The statement should be: never use AI to draft text that is to be presented as your own authorial voice.
Never, never, do that!
I draft all my own text that anyone will ever read as “that’s James Bach talking to me.” I want no one to be able to credibly question that.
But of course, writing is more than merely drafting the text. As I draft, I write about ideas that other people or AI may have helped me come to.