But to the point: the major driver of the early explosion of HIV on the continent was almost certainly large-scale vaccination and medical treatment campaigns by colonial governments, which injected staggering numbers of people in rural areas without adequate disinfection of needles.
In the present, the sociological drivers of HIV spread do include rates of nonconsensual sex (particularly between teen girls and older men). More important factors, however, are historical and contemporary patterns of urban/rural migration and long-distance transit networks. The distinctive forms of cyclical migration created by the shape of the mining industry in apartheid South Africa are the largest reason that the pandemic is so much worse in that region than anywhere else on the continent.
Research is pretty clear that Africans understand that condoms work to prevent HIV transmission - there have now been decades of public education campaigns on the subject. That doesn't mean they are always used, of course, but it's not a knowledge problem.