The visa procedure for South Africans traveling to the United States does not appear to be all that burdensome.
All the Africans have to do is go to the United States Embassy or Consulate, apply for a visa and hop on a plane.
https://www.intergate-immigration.com/american-united-states-visa.php
They can hop on a plane for a visit but they can’t work or live here-——from the link that you provided.
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There is a Visa LOTTERY in RSA, which is not only expensive, but not easy to get.
And a travel visa, to VISIT is one thing; what you and other uneducated loons don't understand, is that just because one has a travel visa doesn't mean that one can stay here...LEGALLY.
Are you suggesting that Afrikaners come here and break the law, becoming damned ILLEGAL ALIENS?