A fad that existed prior to the agricultural fad.
Followers of diets always justify their diet, that's how it stays popular, until it dies out. It wasn't long ago that being gluten-free was the craze. The Adkins diet came & went, same as the fat-free diet. Same will happen with the carnivore diet. I don't care what you eat, go ahead & eat loads of farm raised animals & feel like you are eating like a caveman, makes no difference to me.