So they are "raised specifically for the purpose of feeding people," but just whose purpose? Certainly not the cow's purpose. Is it any the less cruel to confine an animal in a small space, without fresh air or sunlight or exercise, for its entire short life, merely because the corporate owner's "purpose" is to kill it for food? How about the environmental side-effects? The squandering of limited fresh water. The over-use of antibiotics, leading to the evolution of resistant strains of bacteria. The inefficient use of land. The pollution that factory farms are notorious for. Etc., etc., etc. Hereford and Angus cows are not going to go extinct as the result of the slaughterhouse, but modern farming practices are doing incalculable damage to the environment.With cattle, they are raised specifically for the purpose of feeding people and we do not inhumanely cut a small part off and leave the rest. We control the population so that we do not wipe it out. I see these as very different cases. If these dolphins were raised in captivity for this ritual and they were killed in a humane way.....maybe I would switch sides. Maybe.
The cruelty of modern factory farms is certainly comparable to the slaughter of wild animals. With this distinction: Non-industrial societies may be dependent on wild-killed meat for food. In the industrialized world, meat is a luxury, not a necessity. An unhealthy and environmentally-damaging luxury.