I don't get the conversation between msimangu and stephen kumalo in chapter 5 about the whites and black tribes

As you mentioned in your quote,

"Msimangu essentially rejects the notion that the whites have any responsibility for what has occurred in South Africa. He seems to locate both the blame and the solution to the blacks' troubles in themselves, in finding a way to independently rebuild their way of life. "

I think most of the "wise" characters in the book, black and white, tend to put the blame on black South Africa for its troubles.