It sounds to me like you are arguing semantics rather than principle.
One group of you (incl. Pitbull) is sticking to the strict definition (which you get if you google define: apartheid), i.e. " a policy or system of segregation or discrimination on grounds of race". The other group is lumping racial segregation together with other atrocities committed by the NP and calling that Apartheid collectively.
We all agree that Apartheid-era government was terrible and that loads of people suffered terribly as a result.
You cannot, however, deny the fact that the current ANC government legally classifies races and discriminates against certain races based on these classifications using laws (in an attempt to rectify imbalances caused by the old government). In the strict, formal definition sense, this too is "Apartheid", but calling it thus evokes a natural, emotional response beyond the formal definition of the word, because of its other connotations.
TL;DR version: strictly speaking, and formally defined, it is "reverse Apartheid", but calling it thus is really insensitive because of other connotations of the word. So IMHO, Maimane is correct, in a strict sense, but an insensitive ass for the way he phrases it.
EDIT: seems like OD sort of beat me to what I was trying to say.