Using the worst possible methods of ranching and comparing them to the best possible methods of veganism is not really fair.

Pasture animals are not tortured, return carbon to the soil and improve diversity, and can be slaughtered humanely - whereas in nature they die of starvation, or fearful, violent, rending predation.

Meanwhile some forms of veganism increase desertification, remove carbon from soil (and it ends up in the air), requires oil based fertilizer, oil fueled harvesting/transport (sometimes across oceans), and ends up displacing and killing millions of smaller forms of life. My beef at lunch kills one 2000th of a cow, my salad may have killed dozens of birds, mice and insects.

The question is not "Is it ethical?" but "can it be made ethical?" If one really wants to stop the torture and pollution, put your money into locally pastured meats. Because those ranchers don't care what vegans want. They care what their customers want. They will switch from CAFOs to Grassfed if they see a profit.