The essential issue here is that for typical land you can produce more food with plants than you can with animals. Animals act as an extra 'processing' step for food production. Imagine the food chain for eating a plant vs eating an animal. The extra step is highly inefficient by a lot of metrics, but humans have a major diet preference for eating beef/pork/chicken.
Plant -> Person
Plant -> Farm Animal -> Human
Edit: My goal is to explain the basics of the argument that the parent comment was unfamiliar with, not to advocate.
Plant -> Person
Plant -> Farm Animal -> Human
Edit: My goal is to explain the basics of the argument that the parent comment was unfamiliar with, not to advocate.