The vast majority of Afrikaners stayed in South Africa because they consider themselves just as native as their Xhosa or Zulu neighbors. These Afrikaner "refugees" Trumpf took in were unable to psychologically adjust to the fact that "kaffirs" were now in charge of their country. Other Afrikaner and Anglo whites adjusted well in post-apartheid South Africa:
What is so remarkable, contrary to AfriForum's laments, is how much whites have prospered under democracy. White South Africans remain a largely privileged group. Notwithstanding much upward black mobility since 1994, whites are generally richer, better educated, better housed, physically safer, and enjoy better access to health care than their fellow citizens who are black.
Source: Link One
Nota Bene: According to ResearchGate, 20% of the South African Police Service (SAPS) are white. Source: Link Two
