To be far, the boundaries of many African nations were drawn by the colonial powers with little regard for friction between tribes, etc.
Imagine a Baltic nation established in, say, 1700 that was 1/3 Prussian, 1/3 Polish, and 1/3 Russian. Such a nation would be constant turmoil, and would have difficulty stabilizing itself.
Yes, I know that’s not the whole problem, but it does play a part.
To be far -—> To be fair...
Tribal warfare is the special environmental pressure that drives increases in human intelligence while leaving other animals largely untouched. Unlike Asians/Caucasians the Africans did not participate in the long brutal war against the Neanderthals, which is possibly a primary cause of the unequal IQ.
And it is self evident that boundaries did not previously exist, and those chaotic conditions allowed the stronger to victimize the weaker, up to and including becoming slave traders.
The friction between tribes was totally within their control. If it was a paradise in the making before colonization, why didn't it resume after the colonial powers left?