An idiotic hypothosis

I think I mentioned recently that I visited the zoo not too long ago. While reading the signs a poorly informed idea came to me. But first the background.

Reptiles lie in the sun to warm up. Since their body temperature relies on the outside temperature they need to do that to get moving. I'm told that the whole being smooshed by passing cars thing is not part of natures plan and the reptiles that sun themselves on highways will, through natural selection, stop doing that in another few thousand years.

Many species of mammals behave similarly. The furry ones don't tan well and they can control their own temperature so those reasons are ruled out. According to the signs, they do this to kill parasites, bugs, and fungi that would like to live in their fur. These small beings can't handle the sun's UV rays as well as the larger creatures do.

The Naked Mole Rats have no fur. This is because they spend all their lives underground and can't bake away the parasite like the furry mammals must do. They also have life expectancies several times that of the mole rats that do have fur. Just how much longer is still being determined, but so far it's decades. Is this because they don't have the parasites and whatnot that the furry molerats have? Dunno.

So here's how my thinking goes. As the primates that eventually developed into us became more intelligent and started using and building better and better shelters, shelters out of the sun, we became more prone to parasites and the like that would normally have tanned to death. The proto-humans who had less hair also had less parasites et.al and lived longer and had more offspring. Over time they became the thinly haired beings we are today.

One could push this idea a bit further to try to explain why people from sunny areas like the Middle East have more and courser hair than people who developed in the cloudy areas such as the northern European climate.
One could, but it would probably be a bad idea.