There is a fine line between exploitation and a  legitimate structuring of society. A hierarchy of a group is a natural phenomenon in all mammals and ants and lobsters.   To see all hierarchy as exploitation is a mistake. But there can be exploitation also--and often it is not easy to see the difference. You need a balance as the ancient Romans had figured out when there was a peasant rebellion, and instead of making war against them, someone had the brilliant idea of creating institutions that would insure the lives and liberties of the people while leaving the patricians in power to insure law and order. Thus was created the office of the tribune.

    Everyone has a place and just because one is low in the hierarchy  that does nor mean he or she is exploited. But there is a line that can be crossed. The advantage of  some systems is they give one the chance to excel based on ability and competence--not birth.