They are waiting for Mandela to die. After that they will exterminate the white people and starve.
You need to look at the demographics of south africa. They have a sizable asian population and also people who are mixtures of asians-blacks, whites-blacks, whites-asians, and asians-whites-blacks. These people are not going to jump up and start killing off all the whites just because the pure african blacks want it. They know who will be next on the list once the whites are gone. They also know what will happen to jobs once the whites are gone.