The question is, does such practices facilitate the optimal survival of the species.
If we look at Nature and all living things, whether they are purely naked or evolved with something to cover their body besides skin, e.g. fur, shell, feathers, etc. the resultant is to optimize their survival in accordance to their current environment.
Had humans evolved like dolphins, whales and the likes in the oceans, then it would have been optimal for humans to be naked and their genitals hidden behind their skin. [it will not optimal for mermen or mermaids to wear clothes that hinder their speed moving in water]
Evidently from our time line of evolution, humans had evolved to wear clothes to optimize their survival, especially when they migrated from the hotter tropics to the colder temperate conditions and the Artic.
Even in the tropics, humans had evolved with something to cover their genitals [since it is external] and vulnerable to be damaged.
Note;
- The koteka, horim, penis gourd, and Armor Condom is a penis sheath traditionally worn by native male inhabitants of some (mainly highland) ethnic groups in New Guinea to cover their penis.
https://en.wikipedia.org/wiki/Koteka
So it is human nature within our current state of evolution to wear clothes, at the least to cover the genitals to prevent injuries, etc. thus to facilitate survival of the species.
But note the Normal Distribution [Bell Curve]of the continuum from majority to minority.
It is also a very natural phenomenon of evolution, there will always be a small percentile [3 Sigma standard deviation - 3-5%] of humans who will naturally be different from the majority.
Since wearing clothes is the normal things to the majority, the nudist are the 'natural' exceptional small percentage of humans who prefer to go against the current normal nature.
That's the Philosophy of Naturism [Nudism].