South African citizens can apply for a visa at the US Embassy or Consulate and if they can afford an airline ticket, they can leave the country.
I have seen no source that would indicate that South African citizens are being forced by their government to remain in their country.
Bwaaaaaaaaaaaaaaaaaaaaaaahahahahahahahahahahahahahahaha
I also know quite a few ex-pat Afikaners, now living in the USA and their stories.
You don't know what you're talking about.