Boiling a young goat in the very thing that is intended to bring life to the goat would be abhorrent. A goat in the Old Testament was killed for one of two reasons, for food or for atonement for sins. In both instances, the goat is giving up it's life for the good of the people. Not only has the goat's life been taken, but now we're taking something that is intended to give life to the animal, and we're using it to add flavor to the young animal whose life has been taken. This practice would be considered abhorrent mainly because of the blatant misuse of the milk. It's main purpose is life intended for the young, not flavoring to please those who take the life of the young.
It's not unlike the respect that hunters have for the deer that they kill. The hunters I know (and I know quite a few living in Texas), will tell you that one of the most disturbing things that can happen while hunting is that might fail to make a clean kill. That is, they don't shoot the animal in a place where it's death is as quick and painless as possible. Hunting isn't about animal cruelty. It's about finding food for the hunter. No hunter I know wishes to bring pain upon the animal. They recognize that the life that the deer gives brings life to those who take it (via it's meat), and they seek to respect the animal by not bringing more unnecessary suffering upon it.
There's a respect that comes in the exchange of one life for another.
Of course, there are many differing viewpoints. But this is mine.