Brazil, my country, also also had several problems with dictators, overthrown governments and empires trying to make my country in their backyard. But despite that we are in a much better situation than Africa. Why? Notice, we also have corruption in generous quantities.
The question of the AC is valid, period. As always the devil lives in the details, and usually the texts on the subject forget that this question of intelligence (and perhaps racial differences) is only part of the problem alone does not answer the greater question.