Our species has grown beyond the confines of its physical conditioning. Physical strength is no longer as much of an asset as it used to be. Intellectual strength is far more valuable to us now. To allow somebodies intellectual potential to be wasted due to physical weakness would be wasteful.
Materialism, and women's rights have helped to make mating more of an intellectual game for our species than it is for others. So the desired result that humans will become intellectually superior in future generations. We arrest barbarians now, instead of allowing them to rape women and slaughter the weak.
We have stealth planes, and the internet. Whereas the barbarians had wooden clubs and a series of grunting sounds. Tell me who is really weak in the 21st century?