Once upon a time, there was a small apartment in a lower income neighborhood into which a running enthusiast moved a few years back. He was accustomed to going for runs wearing little more than a pair of nylon running shorts and a smile...of course, that was when he lived in a more-metropolitan area and drove to areas where he could run without going by residences.
On his first runs through the neighborhood he received catcalls from the local ladies. He thought little of it, asking himself the rhetorical question "have they never previously seen a half-naked man?" He continued to run sans running top, t-shirt or shirt of any kind until the weather turned cold. At that point he realized his apartment was, like himself, less-suitable for cold temperatures. He then found a new place to live and new routes to run, places where it seemed that going topless was more-acceptable, at least for guys.
As he grew older and experienced setbacks in his battle with the middle-age spread, it became apparent to him that his slightly-expanding torso could be offensive to women, children and small animals. He then decided, "I will cease to run without a shirt for the time being."
"First of all, my heart rate monitor strap, while functional and beneficial at this point in my training, makes me look rather geeky."
"Second, it does not seem fair that I, a middle-aged male, can traipse about public places with my pectorals exposed. If a woman of the female persuasion were to do the same they would most likely be apprehended and forced to provide some financial or penal penance for their outrage to modesty."
As time progressed, he began to understand the rationale behind attire rules which were instituted by large sporting organizations, humorously referred to by some as the "no-nipple rule." It wasn't necessarily that these organizations wanted to limit self-expression or kill joy, more the point that they wanted to make their particular sport more acceptable to the general public. Sure, "wardrobe malfunctions" make for great television, but it's difficult to sell half-dressed persons to potential sponsors. Of course, there are populations who aren't going to accept any sort of "middle ground," this family, for example...