This is based on a complete misunderstanding of the way white people in late 19th and early 20th century southern Africa (and Europe) saw things. The idea that the "natives" could rule the country seemed fantastic. The term "the racial question" referred to British-Boer relations; the "native problem" was something distinct and of far lesser urgency.
"My Lords, forty years ago I was sent to South Africa—my first ever diplomatic post—by the then Dominions Office, later the Commonwealth Relations Office. I was surprised to discover that to Smuts and his contemporaries the words "racial problem" meant the relationship between the British and the Boers. The reconciliation between them on which Smuts's rule as Prime Minister was based, was one of his major achievements; and the liberal Afrikaner element, to whom the noble Lord, Lord Cledwyn, referred, contributed notably to it. But would that Smuts had addressed himself with equal zeal to what he called "the native problem". It would have been an easier one to solve then than it is now..."
https://api.parliament.uk/historic-hansard/lords/1986/jul/04/south-Africa
To give you an idea of how distant black rule in South Africa seemed even to many "enlightened" British socialists: "Comrade Hyndman is probably right that the future of Africa is for the black. Unfortunately, however, that future is anywhere between one thousand and three thousand years to come, the nearest approach to their happiness being, therefore, good laws to guard their standard of comfort..."
https://books.google.com/books?id=-gzMDwAAQBAJ&pg=PT92
As Beatrice Webb later put it, "no one in Great Britain or South Africa seems to have remembered that these various claimants to power, whether Boer or British, agriculturist or gold-miner, were only a minority, a million or so strong, amid a vast majority of Kaffirs, five or six millions in number, amid whom this variegated white minority had intruded itself..."
https://archive.org/details/in.ernet.dli.2015.275455/page/n209/mode/2up