Humans are omnivores: meat and plants. It’s how it is in nature. Anyone who claims that we shouldn’t eat meat is against nature.
I could argue we are actually carnivores capable of imperfectly digesting an omnivore diet. You'll remain in perfect health eating just meat through gluconeogenesis, whereas carbohydrate foods are the root cause of most dietary issues. We can eat carbs and work with it but those foods are not optimal to the human body.