Despite your edit, from what I can tell of being born and raised in the USA, there isn't really a concept of non-sexual nudity, outside of locker rooms/campsite bathouses, some restrooms, and of course, nudist communities/beaches.
Even just taking a leak somewhere that is somewhat secluded if there are no restrooms can land someone a public urination and maybe an indecent exposure charge.
Despite your edit, from what I can tell of being born and raised in the USA, there isn't really a concept of non-sexual nudity, outside of locker rooms/campsite bathouses, some restrooms, and of course, nudist communities/beaches.
Even just taking a leak somewhere that is somewhat secluded if there are no restrooms can land someone a public urination and maybe an indecent exposure charge.