Cycles of Oppression

I have been reading the memoir of Helen Johnson Sirleaf, president of Liberia, who interested me when I covered her appearance at the Press Club some time ago. Her own life is intertwined with the history of Liberia. As most readers know, the country was populated by freed African-American slaves in the nineteenth century. These people retained their American ways and created a colonial society with themselves in power and the indigenous people "colonial" subjects similar to colonies created by European powers. Revolts in recent decades led to other repressive regimes and horrendous civil wars not different from those elsewhere in Africa. Descendants of the original "colonists," known as Americo-Liberians, were persecuted. The story seems to say something very unfortunate about human nature.  Is hierarchy inherent?