You are conveniently lumping T1 & T2 together.
My comment addresses T2 & keto
Not an intentional generalization, but T2 was the intended factor which I happen to have.
My A1c is now less than 6.5 due to the virtual elimination of carbs. It’s a struggle.
I paid a serious price for being too relaxed about the carb intake. So I’m not arbitrarily calling this article into question.