Humans have been butchering apes for food since time immemorial, so why have HIV not been around since time immemorial too? Maybe because HIV comes from something other than butchering of apes for food. As shown in inheritance of acquired characteristics, we all have harmless retroviruses in us, retroviruses that are vital and likely serve as shuttles for bringing adaptive mutations from soma to germline. Is it possible that something have recently started making these normally harmless and important retroviruses mutate into deadly strains?
HIV became a global problem in the late 1970s to early 1980s, but samples of human remains show that it was present in Africa by 1930. It did, in other words, become an African during the colonial period and a global problem at the same time as sociobiology (the direct precursor of evolutionary psychology distinguishable only by being less vague and making more falsifiable predictions than modern evolutionary psychology does) became a mainstream view. During the colonial period, the authorities were systematically spreading racist propaganda that made black Africans believe that they were hopeless victims of fixed hereditary limiting factors and genetically selfish instincts, the same pessimistic self-views that sociobiology later made people all over the world adopt about themselves (yes, all over the world, the Soviet Union had abolished its ban against Mendelism and Darwinism in the 1960s). The global wave did initially disproportionately strike homosexuals, in whose "culture" biodeterministic dogma caught on earlier than in the general population, although that, unlike the even earlier African wave, was not directly due to propaganda spread from outside but to a will to depict themselves as hardwired (which of course was indirectly due to hate and a blame-justify world).
HIV immunity is virtually unheard of in south Europe, but exist in significant numbers in north Europe. Interestingly, south Europe have a stronger christian tradition than north Europe. See multiple stages of justification poisoning.
But what does a pessimistic-fixedistic self-view have to do with HIV? As shown in too many lethal mutations for natural selection to clean up and self-organization, there is so much in the body that can go wrong that a consequence-feedback control is absolutely necessary to prevent the shit from hitting the fan. The placebo effect also affects the body. Believing in the selfish gene hypothesis is likely to cause a nocebo effect (destructive placebo effect). Since the selfish gene hypothesis is about maximal reproduction without ecological or other foresight and denial of the possibility for Lamarckian self-correction, that nocebo effect is likely to make Lamarckian retroviruses at least partially lose their original function and instead start dumb ruthless maximal reproduction, a behavior that mutates them into HIV. The similarity between retroviruses found in apes and HIV can be explained simply by the Lamarckian consequence feedback of apes being close to that of humans. That HIV "mutates rapidly" may simply be an illusion caused by it having many independent origins.
The theory about HIV being a mutated version of retroviruses originally used for passing adaptive mutations from soma to germline explains why it spreads through blood-to-blood contact and sex. Retroviruses ferrying adaptive mutations from soma to germline would most likely be transported by blood and end up in genitals.
The fact that it attacks the immune system can be explained by the fact that the retroviruses in the body normally have as one of their functions to turn off the mother's immune system. However, as shown in inheritance of acquired characteristics, that alone is not enough to explain the necessity of free-moving retroviruses in embryonic and fetal development since the cells could have emitted the necessary chemical signal on their own.
There are most likely many other seriously life-threatening health issues linked to the nocebo effect of believing in biodeterminism/biolimitationism as well.
So the truth is that everybody is really HIV positive. The so-called "HIV negative person" is a mythical beast, the closest real thing being those who keep the retroviruses in check below the threshold of detection. The retroviruses are necessary to stay alive in the face of too many lethal mutations for natural selection to clean up.