Earlier quoted context omitted.
Why is there an ethical problem in slaughtering an animal for meat if that animal has been raised in good conditions and the actual killing happens with a minimum of pain and fear for the animal? I get why foie gras is problematic, but I don't see the problem in a leg of lamb.
Have you seen the movie "The Island"? A organ supplier fakes a post apocalypse for the humans living in the bunkers. They still live a nice life and when they need organs they hold a lottery to see who gets to go to the surface where they've built a resort on an island as they supposedly repopulate. These humans live fairly happy lives and were bred (cloned) to be harvested for the organs. Would you oppose the real w…
However I don't think there's a clear line to be drawn. Why do most people object to eating dog or cat while they have no problem with pork? Pigs are about as intelligent as dogs (and can also learn to recognize individual humans).
Extrapolating that line of thought there is also no fundamental difference between eating plants and animals, but most people argue that it's morally wrong to kill animals for meat but ok to eat plants.