I just listened to the JV show and I thought Sir Muir Grey just came over as one of those obnoxious people who like to create an argument just for the sake of it. He certainly didn't sound much like an expert to me.
It is similar to being told to eat carbs, cabs and more carbs. And low fat everything. And now getting blamed for the resulting crisis, having been guinea pigs for the medical establishment for decades.
In a rather cryptic tweet in response to someone questioning his message he actually agrees in reducing carbs for T2 - although he is on record on endorsing the eatwell diet, at least in general.
He also says to someone who said she knows many T2s who are not overweight and are active fit and otherwise healthy that they are going to be type 1 adult onset. It seems these don't fit his view of diabetes.