When I was in college in Milwaukee I sort of joined National Society of Black Engineers, NSBE, as in, I played for their intramural basketball team, attended a few meetings, and (independent matter) made friends with a number of the members. I don't think I even joined formally, but anyway my then roommate and current business partner Mike Olson challenged me on it. He put up the usual counterexample of the horrified response if he'd started up a white engineer's club. As I recall, I started with a half hearted defense, before admitting that I was uncomfortable with the idea. I'd started out being friends with NSBE members, and never made an explicit, personal, moral stand about the club.
I do think the general idea of exclusion on the basis of race is dangerous, regardless of what past injustices you think you're trying to redress. It's also confusing. I'm raising three mixed race children and where do they fit in with such boundaries. Lori and I generally respond indignantly whenever we're supposed to classify the kids as one race or another. Luckily the census has a mixed race category these days. When they grow up, they can choose to associate as they please, but right now, we have no intention of disrespect to any branch of their rich heritage.
But I'm not a fundamentalist on integration. I understand the occasional motivation for exclusionary clubs. Women's networking groups spring up because even now it's hard for women to find equitable general fora for business. No doubt some other disadvantaged groups such as Black Americans have the same problem, so whereas I think the idea behind NSBE can be dangerous, you won't catch me entirely condemning it. I think some of the most disturbing aspects of the case in the linked article are specific to that case.
For one thing, I read that this blacks-only golf club sees itself as a charity. This beggars common sense considering that they would happily accept "a young, black, successful third-generation, Oxford educated Brit". When you insult the intelligence of those whom you exclude rather than engaging with them to honestly discuss the practical need for exclusion, you're asking for trouble, and you can't expect sympathy.
In South Africa, I think this sort of exclusion is especially problematic because it tarnishes the extraordinary success of the fall of Apartheid. I know and respect a lot of white South Africans, and based on these associations and my following of current events in South Africa, I believe that a gratifying number of the white population in that country is horrified at their racist legacy. Sure, they might not have come to such reform if not for the forceful realities of the freedom movements (much more important than even the infamously leaky sanctions), but all that matters is that they did the right thing in the end, for whatever reasons, and are now largely committed to justice. In turn Mandela, Tutu, etc. showed the most unbelievable courage in fostering an atmosphere of reconciliation. I think the likes of the black golf club causes very dangerous and unnecessary rifts in this peace. Even if it doesn't cause bloody conflict, it will continue the flight of white South Africans out of the country, and I think this a tremendous loss.