The Last King of Scotland

Just got around to watching this movie that I purchased from Play.com to watch over Christmas. I was going to say "Brilliant" "Stunning" - turned over to the back of the DVD and saw that the Mail on Sunday had said the former and The Sunday Telegraph the latter. I was glued to the screen throughout the 117 minutes. The performances of Forest Whitaker and James McAvoy are superb. How do the likes of Amin come to power. (300.000 Ugandans murdered during his regime). Why is it that the African Continent seems to attract dictators such as these?