He simplistically divides humans into two diet groups, vegans and carnivores. This would mean that he considers even vegetarians who consume milk or eggs to be carnivores.
Actually, there are very few humans who are true carnivores, probably fewer than vegans. Most of us are omnivores, with diets that include some combination of vegetables, fruit, meat, fish, milk and eggs. That is what humans have physically evolved to eat.
If we had evolved to live on a vegan diet, perhaps we would be ruminants with multiple stomachs and be spending a lot of time chewing regurgitated matter.