To really talk about African story, and teach this story, you have to teach that tribes were actually nations. You have to teach that chiefs were actually kings, with kingdoms. You have to teach that there was a structure that worked in Africa prior to colonialism. You have to teach that countries were colonized that were doing fine by themselves. And that's uncomfortable.
I am not sure how many "sins" I would recognize in the world. Some would surely be defused by changed circumstances. But I can imagine none that is more irredeemably sinful than the betrayal, the exploitation, of the young by those who should care for them.