DOMINUS saidThe younger straight guys nowadays are fully aware of the preponderance of gay people in their midst, many of whom they can't even identify because many gay people blend in perfectly. Rather than take the risk of gay people staring and salivating at their dingdongs, many of these straight guys tend to cover up. It has nothing to do with body discomfort. It has more to do with their misconception that gay guys at the gym are always looking for an opportunity for cheap thrills and hetero-gay fantasies.
I think that could be a big part of it, too -- the increasing realization that we gays are everywhere, but coupled with negative stereotypes about us.
Incidentally, I have shirts, hats & jackets with the "We're Everywhere" logo on it, marketed to the gay community by a woman I know. Just one way our gay visibility increases all the time, and as more of us come out in public. The towel dance may indicate we still need to work on our image among straights, though.
NOTE: She's closed her own store, and now sells through other outlets, her stuff increasingly difficult to find. If someone would be willing to buy her trademark rights I still think this brand has marketing potential.