Homo as a specie is way older. We started using tools and hunting way before homo sapiens. And even if you want to cherry pick homo sapiens, agriculture is just a minor fraction of his history.
Homo is not a species but a genus therefore considering older and extinct species as reference for our dietary requirements would be unwise. And even before agriculture most of the calories of hunter gathers was coming from plants.
Also https://www.scientificamerican.com/article/why-paleo-diet-ha...
I quote:
Humans come from a fairly generalized line of higher primates, a lineage able to utilize a wide range of plant and animal foods. There is general agreement that the ancestral line (Hominoidea) giving rise to humans was strongly herbivorous (14, 15). Modern human nutritional requirements (eg, the need for a dietary source of vitamin C), features of the modern human gut (haustrated colon), and the modern human pattern of digestive kinetics (similar to that of great apes) suggest an ancestral past in which tropical plant foods formed the basis of the daily diet, with perhaps some opportunistic intake of animal matter.
Going on:
Consumption of animal matter to satisfy requirements for protein and many essential micronutrients would free up space in the gut for carbohydrate-rich plant foods and allow for their use as fuel for the increasingly large human brain (14). Because humans initially evolved in Africa, where wild animals generally lack appreciable fat stores (2), it seems clear that they consumed a mixed diet of animal and plant foods, given the apparent limitations of human digestive physiology to secure adequate daily energy from protein sources alone (4).
Whilst early human were not vegan they were hardly mostly carnivores either. Furthermore as stated in both articles basing the diet of modern humans on the one of our ancestors is a mistake!
P.S. I am far from being vegan! Suturday I ate 600g of a delicious cow.
The other article does seem to be in favor of promoting a vegetarian view. But to me it seems incredibly lackluster:
https://www.sciencedirect.com/science/article/abs/pii/S08999...
To shorten it up:
1) Today we suffer of diet related disease
2) Other great apes are mostly vegetarians
3) Our digestive system is very similar to that of apes
result:
The recommendation that Americans consume more fresh fruits and vegetables in greater variety appears well supported by data on the diets of free-ranging monkeys and apes.
Previously our differences from apes have been correlated to the fact that we cook food:
Thus, humans are relatively poor among autoenzyme-dependent omnivores in digesting uncooked plant fiber. The human large intestine lies somewhere between that of the pig, a similar omni-vore, and the dog, a carnivore capable of consuming an omnivore diet that has a reduced cecum and short colon.