How was Africa disconnected from South Africa?

South Africa is the southernmost country on the African continent. It is not, and never was, disconnected from the rest of Africa, not in a literal sense, that is.
But in the days of apartheid there were vast ideological differences dividing South Africa and the rest of Africa where former colonies of European powers had achieved independence. Save for a few African countries bordering South Africa -- countries that were economically obliged to maintain ties with it -- Africa as a continent severed all relations with the south. South African planes were not even allowed to fly over Africa to Europe, but had to take the route above the Atlantic Ocean to the west.