So that makes all the ethnic groups into a single ethnic group now? What happens when the Apartheid era fades from memory?
So basically, a bunch of similar but still quite distinct ethnic groups (Bantu and Non-Bantu Black Africans in South Africa) are unified because of their experience of brutal repression, but other ethnic groups elsewhere (Slavs, Albanians, Cacasus peoples, Turkic groups) could not have had the same outcome with different leaderships because.....?
Really, South Africa did not have to go the way it did (EDIT: Just look next door at Zimbabwe where a similar experience of harsh minority rule did not lead to early cohesion among Black Zimbabweans as very shortly after Zimbabwe's new ruler (from the majority Shona people) initiated a massacre against Ndebele civilians; thankfully that didn't develop into anything further although the potential was there. /EDIT). Mandela did the country a huge favour in how he handled the transition from apartheid to democracy. On the other hand Yeltsin, Tudjman and Milosevic did their respective countries no such favours.
All black Africans in South Africa are Bantus, unless they are immigrants from West Africa or something.
And to be fair, there was violence in South Africa in the late 1980s and early 990s between black people, between the ANC and the IFP. The latter was primarily Zulu, with the former being more mixed (although having many Zulu members, Jacob Zuma is such an example).