Nice comparison. Punching somebody in the face actually harms another human being.
Harms how? Because it inflicts the sensation of pain? What if the person has a condition where they cannot feel pain?
Because it causes physical damage? What if it's only a light slap across the face?
Because it creates unwanted contact on their body? What gives them the right to not have their body touched if that's what I want to do?
You cannot answer these questions without folding on yourself. Because at the end of the day,
it's all about socially acceptable behavior. Society deems the behavior of a certain quality, regardless of your personal feelings on the matter.
Being offended at somebody's body is not the same as being harmed.
How about two teenagers who are dry humping in the middle of a parking lot? There's not even any nudity involved. Nothing wrong with that, right? Hell, why don't we just go ahead and make it full blown sex by 3 women, 4 men, and a donkey? Why should
that be prohibited in public? It's just the beauty of the human body. And the beauty of the donkey too. They're always naked, so it's all good. Right?