Bro, the ball before DuPlessis got dismissed, there was a big drama happened in the name of DRS. India reviewed for a lbw decision and the result was umpires call since the ball was hitting the top of the stumps. Actually it was really out. The margin for umpires call was really less so India were unlucky not to get that wicket and the SA players and crowd reactions made Kohli, Pandya and others frustrated. Hence the outburst was natural when they got his wicket legally the very next ball. India deserved that wicket.
I'm not defending Kohli here but this time its not his fault. But in general as a captain he should control his emotions if not like Dhoni, atleast like Greame Smith. But these days cricket is no more a gentlemen game. All captains are like that.