Prior to the colonial era, genocidal actions were common, with the Mfecane and eradication of Koi Bushmen by black African hordes as they marched South and West in colonial expansion. Not really!
The Mfecane was more of an unintended knock-on effect when clans in Natal (Zululand) fled the brutal rule of Shaka. As they fled westward, they displaced other clans, and because of the upheaval, the people in the interior stopped growing crops and thus starved (actually resorted to cannibalism).  It was not colonial expansion under Shaka that caused the Mfecane. As for the Bushmen, they moved into Natal from the west to the foothills of the Drakensberg and clashed with the Zulus over land and cattle and dominance.
Actually, in the time of Shaka, traders established a small settlement at Port Natal (as Durban was first called) and a few American missionaries arrived to evangelise among the Zulus.