Someone who believes that the only cost of raising food is land area.
When the simple truth is you can apply more labor, machines and chemicals to plant farming per area than to ranching animals because plants are less "alive" or sensitive. But that does not mean more effective unless you are planning to populate every possible square inch of the Earth with humans. Doesn't that objection to being raised in dense confinement and on restricted diet apply to people as well as animals?
First vegetarians forget organic farming is dependent on animal ranching for fertilizer. Human waste alone would be diminishing returns.
Vegetarians forget to mention that 3rd world farmers can ranch meat animals by simply turning them loose on any land with any plants and gather them up when ready to harvest. The labor is limited to protecting from theft, predators, and occasional birth assistance. No machines or chemicals required.
Vegetarians lie and describe the cost of farming as if plant farmers are only gatherers of wild produce. Real vegetable farming requires a lot more labor in tilling soil, gathering, and storage plus pest and weed control than animal ranching.
Vegetarians "forget" to mention that a lot less land area is suitable for human edible plant farming than animal farming. And the sea is almost zero directly human edible plants. Animals can eat many plants humans cannot.
On a modern scale grains and vegetable are far more machinery and cash intensive than raising animals for meat even when divided among the people that can be fed -- assuming that you do not restrict the amount of land and water the rancher can use.