Bodies that were not made for a hot, dry East African climate
Minibuses with no air conditioning and with an extra heater were probably made for a cold climate, not a hot one. Using similar logic, human bodies, with no fur for sun protection, and with a sweat-cooling system that uses up to a liter of salty fluid per hour, were probably not made for the hot, dry East African climate. I think the human body evolved on rainy Bioko island, off the coast of western Africa.
Icy Norwegian roads are salted in the winter, and cars here get rusty. I have a 30-year old Mercedes minibus that I use for hauling rocks and students on geological field trips. It is the fourth old minibus that I have had. When these minibuses are too rusty to last much longer, they are sent to Africa, where the rusting will cease, and they can be used for many more years as share-taxis.
It you looked objectively at one of these rusty minibuses in Africa, you would understand that it was not in its original habitat. It might still have snow tires with the metal studs removed. You might notice its built-in heater under the back seats. It has an electric engine-warmer, so that it can be pre-warmed to start on cold winter mornings. It has insulated passenger windows, that cannot be opened on hot days. And it has no air conditioner at all.
You don't see such old minibuses here in Norway, but you might fine a few in East Africa. This is similar to gorillas and chimpanzees. You won't find fossils of them in their original habitats of central and western Africa. That is because bones decay in those habitats, and don't survive as fossils. But three chimpanzee teeth have been found in East Africa. No other fossils are known of chimpanzees or gorillas.
Human features suggest to me that human bodies were built for a place like Bioko island. It is one of the ten rainiest places on Earth, so there is plenty of fresh water and salt. The temperatures in the air and the ocean are comfortable all year round. Fur would not be needed there, because the nights are never cold, and there is no blazing sun that would burn the skin during the day.