Humans are more similar to herbivore than omnivores or carnivores. In particular, our teeth and long intestines match that of a herbivore. Humans have only recently started eating meat due to the development of fire and hand made knifes. The human digestive system is not as acidic and is much longer than that of a other carnivores or omnivores. Humans started to eat meat after the advent of fire, to cook off the deadly bacteria that make herbivores sick.
Omnivores and carnivores tend to have claws for ripping flesh. Humans do not. Only once knives were invented did humans start hunting animals for consumption. Humans can eat cut up and cooked animal flesh, but it's not the ideal food for the human digestive system.
Here is a comparison of digestive system comparison showing
Humans digestive system matches those of other herbivores:
Humans teeth match those of herbivores, not omnivores or carnivorous.
This video explains it in a comical and simple way:
It's more scientifically accurate to called a human an herbivore, that can eat meat. In the same way we call a cat a carnivore, even though anyone who owns a cat knows they eat grass on a regular basis. Does that make them an omnivore? No.
Humans are scientifically herbivore but due to the fact that humans eat meat, makes them practically omnivores.