Answer:
Humans only care about something being slaughtered if its "theirs." Or they see it as thier own in any sort of way. We care less about the neighbor's pet being hit by a car that "our: pet being hit by a car. Same goes for children. "Thier" child is being stolen, it makes the person feel sad, but mostly pity, for the 'owners' of that child. "My" child is being stolen, makes the person much more concerned about the situation bcs the child was "Thiers."
Expl anation:
If people could detatch themselfs from auto-claiming children. They most likely wouldn't have a problem whatsoever with this situation. It'd be the exact same as selling farm animals, which these kids would become.