I am sure it is a very one sided history.
It might be useful to know what the Germans wrote about this episode, say in 1910.
Africa was far from a peaceful place prior to colonization. Arab slave traders massacred and enslaved millions. Tribal warfare was almost unceasing. Cannibalism was rampant. Witch doctors ruled villages with terror.
Compare the European rule with what they displaced, not some impossible Utopian ideal that does not exist, and never existed.
Compare the European conquest and rule with contemporary alternatives. What happened when the Zulus conquered? When the Arabs conquered? Those are real comparisons.
Namibia waw very far away from the Arab slave trade