I come from a culture that has no nudity taboo - nudity is not considered inherently sexual, or somehow traumatising to witness. What that means in practice is that there is a clearly drawn line between sexual and non-sexual nudity. There is nothing wrong or inappropriate about nudity in a sexual context, and nothing wrong or inappropriate about nudity in a non-sexual context. However, it is 100% inappropriate to be nude in a situation where it is not obvious from context whether this is sexual or not.
I've seen random kids who briefly escaped from their parents bolt across a public park buck-ass naked after they were playing in the water fountain and their parents were in the middle of changing their kid from wet clothes to dry clothes when the small nudist escaped. Changing your small kid's clothes right there in public is ok because there is obviously nothing sexual about a child whose clothes got wet. But although people will have baby pictures of their kids in the bath or just running around the house like that because sometimes little apes hate clothes for some reason, it's considered common sense to not share those pictures on facebook mom groups and such, because you have no way of knowing who's seeing them, and that blurs the line of context.
It all boils down to the clearly defined context. Bathing nude in the same sauna with five of your co-workers at the office christmas party? Clearly nonsexual, therefore completely fine. Your friend-with-benefits inviting you to come over and opening the door in nothing but a doggy collar and the most porn-scented perfume? Clearly sexual, therefore completely fine. A woman checking her breasts for lumps in the gym lockers just before or after a shower? Clearly non-sexual, therefore completely fine.
But if you went to the bank today and there's some guy who walks in and immediately strips naked, doing his banking business wearing nothing but a deep smile and being clearly very content with this situation, you have no way of telling whether he's getting kicks out of this or not. There is no contextual reason for him to be nude. Therefore, that is inappropriate.
Then you go home and post on tumblr - as one does - going like "there was some dude completely fucking buck-ass naked in the bank today. That was fucking weird and I wish he had not done that." And someone immediately swoops into inform you that actually nudity is not inherently sexual or inappropriate, and there are cultures out there that have no nudity taboo. It's not fair to call somebody a freak for something like that, maybe that guy was just finnish.
