Can you clarify what you mean by 'demand control over another person's body? '
I mean demand that they cover up or be forced to cover up (or face removal). I think it's entirely reasonable to have and voice concerns, preferences and requests.
Is the law demanding we drive on the left (UK) demanding control over another person's body? (Trying to think of an analogue that we all accept).
Yes, I think it is but I would say that's a decision made because coherent decisions between are required when operating motor vehicles at a reasonable speed. For the same reason, we typically require one approach to a junction to yield, if lights aren't provided, to reduce the amount of slowing required on the main thoroughfare.
I don't think (might be wrong) that any kind of fetish wear would break the law whereas being naked may do depending on circumstances.
Scotland may be a different case but the law seems rather vague to me (outraging public decency/breach of the peace) and I can see either offence applying in both scenarios.
Does your discomfort stem from nakedness being 'natural' and fetish wear up a mountain being deliberately shocking? Would be interesting to unpick why the difference?
For me personally, it would come down to my perception that there are more naturists than flashers while fetishwear, on the balance of probabilities, is probably worn as part of a sexual fetish. This is just my perception, I'm not claiming logical or moral authority on relative discomfort, merely expressing how different people might react differently. It's likely down to my having encountered naturists and finding them to be odd but generally more agreeable than the average person on the high street. By comparison, I have almost no experience talking to overt fetishwear-wearers.