I guess we agree.
I don't argue that we should continue todays consumption, only that going all vegan might not be a good idea.
Reducing consumption seems like a really good idea to me for several reasons. As does small scale poultry and animal farming (raising a pig or some poultry on scraps instead of throwing it away should be a good idea today as well if one could get away with it.)
Our ancestors generally ate far less meat.
They could also feed smaller animals like poultry on scraps of food, which doesn't really scale to feeding the billions of animals we currently raise for food.