Yes, South Africa is dangerous. But it doesn't prevent people from living normal lives. There's a good health care system (if you're willing to pay for it), good schools, good jobs, competent people.
There is racism, just like there is racism all over the world. I don't believe crimes are racially motivated, though, since all races are victims of crime over there.
You just need to be careful over there and don't put yourself in situations that can lead to disaster. For example, you don't walk over there, you drive everywhere. Especially if you are a female. You don't wear lots of jewelry either. And you make sure you insure your possessions properly.