They are just angry that the most successful South African happens to be a White guy now living in America. He is the worlds richest man and a LEGAL immigrant in America from South Africa and it makes their brain hurt to even try to think about it. They also hate him for taking away one of their online echo chambers where they spent all day circle jerking about how smart they are and how dumb everyone else (the right) are and now the "dissenting voices" can argue with them on flat ground. They have found that their ideas and shitty toxic culture can only exist in a vacuum where all other ideas are forcefully rejected/shut down and they are mad as hell.