The problem is and I understand this thread has descended into naked bosom clasping the law is supposed to be blind. You can't say, this guy seems harmless to me, that guy doesn't. If a creepy, naked man was hanging around my children, I would want them not doing it. But it is not that different to this. You can't have the law so mutable. It is already a racist, sexist and discriminatory world even with laws that can be universally applied.
BTW if we were a society like Sweden where everyone likes to be naked all the time I think it would be a bit different. But as it stands nakedness in public is not usual and the interpretation is that he is doing it to shock.