I don't think you get to count Australia, NZ, US or Canada here. For the most part, colonization in those places was a process of removing the indigenous popul

I don't think you get to count Australia, NZ, US or Canada here. For the most part, colonization in those places was a process of removing the indigenous populations to make room the offspring of the colonial power's settlers. That allowed the colonizing countries to export their political systems wholesale, including cultural expectations and created a relative tabula rasa for historical grudges (though there are some that we still see ripples of today, e.g. in Quebec and Appalachia). On the other hand, most of the colonization of Africa was characterized by, er, conscripting the local population as labor forces for extractive industries (running from slavery in the 17th century to minerals today). The colonial powers imposed controlling political systems onto groups of people who had their own histories, political cultures (read: methods of conflict resolution) and grudges. Since the colonizers were running the colonies solely for extraction without expectation for economic growth, they didn't prioritize economic and political self-sustaining capability in drawing borders; that those borders have remained in place after the withdrawal of colonial life support has been the source of much of the economic struggle (which begets violence, which begets destructive undevelopment, which begets further economic struggle).