The idea behind it is that it is like loot in war and that those who win can become the rulers and choose who gets positions. It doens't have to be corrupt since corruption is criminal activity and these people can actually do well. Many consider it to not be ethical, but it doesn't have to be corrupt.
One of the most important factors as to why babylonian and sumerian societies were different was that they focused on different economic priorities, which shaped the cultures.
