"It doesn't just come from nowhere."
Thanks for your replies, Lisa and Conor. I was hinting at religion. For the record, I am a Christian (and a creationist). Conor, the concepts you describe above seem more suited as legal concepts than as moral concepts. I don't think that "Right" and "Wrong" change. Under the above circumstances, that is, morality determined by open discussion, right and wrong could change. Thus we enter the debate of absolute morality vs. postmodernism. This is surely something we didn't intend to get into in the comments of an animal rights article.
Suffice it to say, however, that there are parts of your arguments about the meat production system that I could agree with. After all, to Christians, humans have dominion over the animals, the land, etc., but we are required to be good stewards.
Thanks for considering my comments.
"Predation is part of the Earth's ecosystem, and for that reason I would find it hard to argue that killing animals for food is inherently wrong in the same way that killing people (for whatever reason) is inherently wrong."
What makes it inherently wrong for a person to kill a person for food? In fact, what makes anything inherently "wrong?"