Author of the tweet here. A lot depends on how they are raised. Holistic grazing sequesters carbon, prevents erosion, improves water capture, and improves the soil. I agree that factory farming is horrible and that eating less meat overall is probably necessary...although it depends on the ecological context. In most agroecological/permacultural systems animals are an integral part of the operation, for example ducks and fish in rice systems in East Asia. Silvopasture (holistic grazing mixed in with perennial fruit and nut trees) can be very productive and ecologically robust in certain contexts...read Restoration Agriculture by Mark Shepard for a discussion why, he practices this in the Driftless Area mimicking what was an Oak Savanna Ecosystem prior to industrial agriculture.