Here, I'll make it more clear to you by defining what is not too far first.
In 2023 a bunch of nude cyclists were present during the public Seattle Pride Parade, while they were fully naked, half covered, etc. Their behavior is very clearly artistic expression and not inappropriate, as they were wearing body paint and commiting to other artistic representations of nudity no different from a body paint artist that are also very public in Seattle, nor were they engaging in inappropriate behavior or attempting to induce sexual arousal. In the same vein, wearing a rubber suit can also very much fall into the same category.
Does that make it more clear?
The specific cases are those intentionally engaging in behavior that can't be defined as artistic expression and can deeply harm the overall movement, such as the rare cases of inappropriate touching/unwanted touching.
Imo, strict codes of conduct such as those used by Nudist organizations during their public events in other more lax countries should be used, not only to discourage the behavior but to also protect the integrity of the events and movements when such cases do occur. The mentioned Seattle Pride Parade for example had no official code of conduct, luckily no such case occured during this particular event.