Honestly, with the exception of Denys Hobson during the Apartheid Ban I don't think that South Africa has ever had a spinner worthy of being selected.
I'm deeply unimpressed by Maharaj: I can see why Shamsi has more potential.
It's not that I "want a white team."
For me the issues are that:
1. A country whose playing base is 4 million whites can't afford to omit any players who should be selected on merit.
2. I doubt that cricket will ever get a foothold in the African population, rather like only private schoolboys ever play rugby union in England and Australia.
3. Even players like Rabada and Bavuma were either born into wealth and privilege (Rabada) or attended an elite school (Bavuma).
4. Pay for South African international players is atrocious. Low wages cultivate fixing in poorer - mainly non-white - players, and encourage white players who don't fit inside the "best five white players" quota to emigrate.
5. That white flight exacerbates domestic quotas by weakening the quality in domestic cricket, which goes on to slow the development of non-white players.
It's a big mess. It's heading in the Zimbabwe direction.
Apart from Majraj part, which I have confessed last time - I'll never discuss Spinners with an Englishman, I don't completely disagree with any of your points apart from No. 1 - but, you have to look at both ways for your five points -
1. 4mn or 40mn, doesn't matter, no player should be omitted from racial quota - that's completely agreed. But, that's not the case here - by chance or by design, 5 non whites are performing in the team - it's the white players that have under performed or didn't bother to fight it out. Why should a non white SAF players made to pay for those? Non white SAF's are not making the team out of color quota only - rather the whites are just not good enough and failing to cement their spot.
2. If that's the case, then cricket'll get extinct from SAF. It's their country & they are 85%+ brutal majority - if they are not interested, the game won't survive there; you can't keep it alive by live support with few whites interested in the game. I see it other way - it's the only way for cricket to survive in SAF is to bring non whites in the game. What you are saying (blacks would ever have foothold), if true then in Soccer Brazil won't have been Brazil, or USA won't have been USA in Basketball - 100 years ago, Brazil had 1 (or 2) "Niger" (no disrespect) in it's Olympic football team ....... Even for ENG, I believe Viv Anderson was the first black (non white) players winning ENG Cap in 1977 - now, that same ENG team has at least 6 Black/non white starters - Clyne, Smalling, Walker, Sturridge, Sterling, Alli - add to that Bertrand, Rashford, Alex Ox, Defoe, Livermore, Rose, Gibbs, Walcott, Welback ...... not sure what you can prove here.
3. That's just the start - Apartheid SAF had deprived non whites for centuries, therefore they are several generation behind. Now, only those having a little privilege are making it, in future it should reach to the mass level. For example, Kumar Sri Ranji or Dulip were Maharaja, Iftekhar was Nawab of Pataudi, Jahagir Khan (Majid's father) was a barrister in 1930s - they played for ENG, because they got the chance to learn the game. But, 50 years later Vinod Kambli is making it from Mumbai slam, Razzqq was a day laborer at a motor mechanic shop, our Rafique is one of 8 childs of a day laborer mom, with their father leaving them at childhood .............. talent needs opportunity to flourish, not social class.
4. This one I can't tell - but, I explained several times that MoHa can't & shouldn't complain what Yuvraz is earning, while YV can't complain what Alex Rod is earning at NY Yankees. That's a problem across all section - why should whites only react to that? And, that's a problem for cricket vs football or golf, not white vs black.
5. Domestic quota may be weakening the system; but this is the only way to bring non whites in the game, so that in future there is a strong non white base. Also, every injustice balances out over time - that's the learning from history. For example, if you put several white names from 50s & 60s SAF team - even you'll be surprised to think, how this guy played Test cricket, sometimes even Captaining the side ..... Here, they are just balancing it a bit. Once, there is enough non white players - it won't be required.
I reiterate - I am not for any such quota, but I understand what's the reasons behind it. If it ends like ZIM, that'll be because of another Robert Mughabe type, not for bringing blacks in the game.