There is a big difference between “This is not my story, but I am telling as best I know”, and “This may as well be my story, and I can change what I like.”

The whole White people poking fun at Black dictators was probably seen (with some truth) as less satirising Idi Amin (say), than using him to make a point about how all black black African leaders are ridiculous figures, aping their white betters badly.

Now, on the other hand, we can contrast Mugabe against Mandela.