The first time I noticed an increase in revisionist nostalgia for southern Africa’s white supremacist states was in 2015, when a maladjusted 21-year-old man called Dylann Roof killed nine black people in a church in South Carolina. Roof had taken numerous photographs of himself wearing a jacket emblazoned with the Rhodesian, apartheid South African and Confederate flags, and had published a manifesto on a website called “The Last Rhodesian” in which he declared: “Look at South Africa, and how such a small minority held the black in apartheid for years and years… if anyone thinks that think [sic] will eventually...