Noah asks a good question, and I wish I could answer it more adequately than I will.
One distinction that immediately leaps to mind is that between keeping a pet in and around the house just as a loosely attached being whose role in the life of the family is viewed by its members as ordered simply toward the provision of meat, and having a pet that is viewed – perhaps absurdly, as some might insist, though obviously these things come in degrees – as a part of the family, as “one of us”. The latter model is of course the one that predominates in American households, and I can imagine that e.g. Rod might have had a good deal more trouble serving up the dumplings with that hen who turned out to be a rooster if he’d given it a name and allowed it to curl up with him on the couch; by contrast, I recall a friend from Kansas describing a family who’d bought a calf and straightaway named it “Meatball”, just so the kids wouldn’t get any illusions. (Perhaps the person who really ought to be taking on this question is Caleb Stegall.) Hence the relevant question would be: When e.g. a South Korean family has a dog around the house that they plan to put into a stew, do they view and treat it in the same sorts of ways that most Americans treat their pets? The bonds of attachment and affection that such treatment naturally engenders would, it seems to me, make it a great deal more difficult to go in for the kill.
But on the more general question of the relative merits and demerits of knowing where your food comes from versus, well, knowing your food, it strikes me as perfectly reasonable for the ethically-concerned meat eater to think that the second alternative is the superior one, at least in the abstract. Part of the reason why I prefer, say, buying beef by the whole or half steer instead of a cut at a time is that it enables the focusing of one’s attention on the distinctive sort of sacrifice that meat-eating requires; the family members can direct their gratitude toward the life of the particular animal whose death made their sustenance possible. And such an attitude is likely to be further strengthened when the animal was one with which the family had some real contact, not to mention the memory of a time during which they sustained it in much the same way that it is now sustaining them.
None of this is to deny that a close and personal relationship to the sources of one’s steaks is the sort of thing that would make the average meat eater, myself very much included, unpleasantly troubled by what that luxury requires. Then again, a bit more such discomfort might not be a bad thing at all. Raising, slaughtering, and consuming our fellow animals are activities fraught with mystery and a good deal of darkness, and it’s at our peril that we drive those qualities too thoroughly from our conscious minds.