I don't remember who the comedian was, but the joke comes to mind as I ponder this topic. It was a joke about seeing her naked husband bent over the bathtub. The punch line was something like, "I thought he was a mountain goat!"
The joke landed right and was funny because there was truth in it. That truth is that you cannot really look at human private parts and not acknowledge their similarities to the non-human animal world. Our bodies and our bodily functions are so similar to other mammals that there is almost no mistaking the fact that humans are animals when you see the human form unclothed. Therein presents a problem for some of our modern mythology about the human place in the world.
Since the fall of the Pagans and the rise of Medieval Christianity, humans have pretended to be separate from, different from or better than animals and nature. We have told ourselves many lies in trying to perpetuate that myth; animals don't use tools; animals don't communicate; animals are stupid and naked. Humans, by contrast, are smart, use tools, communicate and are not naked.
As I have previously written, the origin of human body-shaming is partly rooted in slavery. That is largely because humans were trying to assert a superiority to nature and animals, the idea being that slaves were mere animals that were naked (never mind that slave owners kept them that way). To be human (and, therefore, superior) you must be clothed. The more expensive and elaborate the clothing, the better of a human you must be, the mythology goes. We see this today with our continuous obsession over clothing style and fashion. It is also why, in part, some people can be so offended by the sight of a naked body, or something so basic as a breast-feeding mother. These sights challenge the myth that humans are not animals. That is really uncomfortable for people who cling to that myth tightly.
The problem with this thinking, of course, is that humans are animals and we are part of nature. As the Native Americans tried to tell us as we were killing Bison to near extinction, what we do to nature, we do to ourselves. Understanding the profound reality that we are, in fact, dependent on nature and the environment requires that we embrace the human animal, which we all fundamentally know is there, but which we are forced to keep hidden due to these made-up cultural beliefs.
It is my belief that part of the reason nudists/naturists experience a profound sense of freedom from taking off their clothing is that doing so allows us to experience being part of the world around us as we are without this mythology. Shedding those beliefs is uplifting, empowering and healing. We should all do more of it.