That is indeed surprising, because one thing I was told time and time again in SA -- and mostly by white people -- is that there simply wasn't white opposition to apartheid outside of a tiny handful (and old white people claiming today to have opposed it back then are hardly to be taken seriously). But Sixto records went platinum, so his audience must have encompassed many more white people.
Well, "people with a progressive viewpoint" is not exactly the same thing as "organised opposition".
The first is nigh inevitable for some percent of the population. The second is not. In fact a repressive state will turn it's efforts into preventing such people connecting, organising, etc. Giving them the message that it is best for them to keep their heads down and keep quiet, and not join a "movement".
That is why, in repressive state, any non-state social movement would be viewed a potential threat, even if it claims to be not political at all.
> and old white people claiming today to have opposed it back then are hardly to be taken seriously
Sounds almost like you are trolling.
There are number of ways of opposition. Most people just want to get on with their lives though and you don't have the time nor energy to protest. There were tons of different viewpoints from all population groups. It's not as black and white as you've been reading on the Internet.
> It's not as black and white as you've been reading on the Internet.
As I said, my understanding has been formed by what I was told by local people while in SA. I have never actually read much about this matter on the internet.