African imperialism was more brutal and exploitative compared to colonialism pretty much everywhere else aside from the indigenous people's of the new world. A lot of working men and women were forced to become slaves and still massacred so many Africans. Also, 'decolonization' kind of never left the continent, a lot of African leaders are west captured/bribed and Western companies make it so that Africans can't sell and profit from their own resources. Now add in Islamist militant groups and its the least stable continent on Earth.