You are free to take it as literally as you want, but it seems like it would allude to milestones in evolution:
* As we get closer to the modern human, we lose body hair to better suit our hunting style. The trade off is we're much more vulnerable since our skin is pretty bad compared to almost every animal out there.
* We make up for this by literally taking other animals' skins and putting it on top of our own.
* Hunting societies begin to emerge in parallel to this change, and shame is a key element of the social interaction that allows that. Shame allows reinforcement and communication of expectations, all without violence or even language. Being exposed means that you cannot even take care of yourself, so you have to be able to show you are ashamed otherwise it means you're absolutely clueless and why would the group want you around if you're clueless?
> "our skin is pretty bad compared to almost every animal out there."
Our skin is awesome compared to almost every animal out there. No other animal can sweat like we do, which is essential to keep our body temperature down during long periods of exertion. Humans can hunt almost any animal to exhaustion. We may not be fast, but we've got way more endurance than any other land-based animal, and our skin is a big part of that.
(Admittedly you alluded to this with "to better suit our hunting style", but I thought I'd make this more explicit. Human skin is fantastic.)
I am no anthropologist. A quick search on the topic (not specific to those people) suggests decoration, identity, and "perception of how to live life" are possible reasons.
> Gilligan points out that humans were probably decorating themselves long before clothes even existed. "When you look at contemporary hunter-gatherers who don't use clothing, they decorate themselves brilliantly with body painting. You don't need clothing in order to do that."
> a hunter, before he tracks his prey, must cut himself and rub the cuts with a root called ssho /oa. And he must rub his body with it and wear ssho /oa in a band around his shoulders. This is to get the game to “run foolishly”, not knowing that it is afraid, and to approach the hunter as an equal. ...
> Far from being naked, or nearly naked, the Bushmen of colonial southern Africa had a complex and meaningful practice of dress. It was intimately related to subsistence, identity and their perception of how to live life in the world as they knew it.
* As we get closer to the modern human, we lose body hair to better suit our hunting style. The trade off is we're much more vulnerable since our skin is pretty bad compared to almost every animal out there.
* We make up for this by literally taking other animals' skins and putting it on top of our own.
* Hunting societies begin to emerge in parallel to this change, and shame is a key element of the social interaction that allows that. Shame allows reinforcement and communication of expectations, all without violence or even language. Being exposed means that you cannot even take care of yourself, so you have to be able to show you are ashamed otherwise it means you're absolutely clueless and why would the group want you around if you're clueless?