This is probably why you're getting downvotes; it's the idealism and certainty with which you determine a human's ideal diet.
We cannot say with certainty what the ideal human diet is. And what's ideal for one group isn't ideal for another. For example: most Northern Europeans are adapted to digest fresh milk while East Asians are not.
I can't say with certainty what the best human diet is. But I can say it is highly probable that the ideal human diet includes some meat, and it's highly probable that humans cannot thrive on a plants-only diet. This is evidenced by no plants-only diet peoples in existence today, other than vegans, which are a young group, untested by time. And time is the greatest filter.
The longer something has been around, the higher the probability it is a good thing, and the higher the probability it will continue to stick around. And plant-only diet peoples haven't been around very long. Contrast that with peoples who eat meat, who have existed for millions of years.
Vegans must eat some foods enriched with b vitamins to survive so they are not really on a plants only diet either. An entirely raw food, plant only diet leads to a horrible death due to b12 deficiency.
This is probably why you're getting downvotes; it's the idealism and certainty with which you determine a human's ideal diet.
We cannot say with certainty what the ideal human diet is. And what's ideal for one group isn't ideal for another. For example: most Northern Europeans are adapted to digest fresh milk while East Asians are not.
I can't say with certainty what the best human diet is. But I can say it is highly probable that the ideal human diet includes some meat, and it's highly probable that humans cannot thrive on a plants-only diet. This is evidenced by no plants-only diet peoples in existence today, other than vegans, which are a young group, untested by time. And time is the greatest filter.
The longer something has been around, the higher the probability it is a good thing, and the higher the probability it will continue to stick around. And plant-only diet peoples haven't been around very long. Contrast that with peoples who eat meat, who have existed for millions of years.