It's evolution of human societies really. And like all evolution it's not moral, nor has any higher purpose. Different models compete with each other, the capacity to survive, expand and evolve is what is being tested.

Preying is part of life. People forget we are animals. Sure, we try to impose some rules on the preying, but who can enforce them but the strongest?

I am not trying to deny our need for liberty and safety. But you have to think about those in the real context of constant conflict. At any time you should look around and chose to support one predator over another, because there are real differences that will impact your needs. And many people from that time and place in the original article chose the white wolves.

Edit to address you question more directly: empires need to provide some things to the ones who are being ruled, otherwise you can't keep order. Lack of order means lack of efficiency, which affects army, which affects their ability to control and expand the empire. So there is a constant quest for balance between taking resources and giving back things. New empires pop up that do it better and they kill everything around until they fall themselves. Evolution.