I am an Afrikaans native speaker and if it is what it is alluded to in our SA media (and this piece) it is just a rugby call that we make the whole time. The word that Curry think he used is not really in South African lexicon as we have our own dedicated words for that type of vulgar type of speech. Whenever I have payed rugby we have always spoken Afrikaans, because the vast majority of the players will be Afrikaans. Bongi played at the Stormers so I am pretty sure he would also do all his rugby calls in Afrikaans.
Jersey Colour: groen (green) = South Africa/Ireland wit (white) = England Swart (Black) = NZ etc
kant (said like the word in the article) = side
So wit kant would mean on England's side
If it is not that, then it needs to be looked into and he will need to face the punishment. Let's wait for the investigation to finish before we crucify him.