I'd often thought about this, if we were not given the proper gender status then it would be perfectly okay to go topless and mow the lawn, wash the car, go for a bike ride etc. Where do they draw the line between "moobs" and indecent exposure? Sounds like a judgment call to me based on what some male finds pleasing or not? What if a man was just femme looking and had moobs?
I am sure they have catch-all laws like "intent to cause a public disturbance" etc to cover things they have not managed to spell out in specifics.