I don't mean mock like, "Hey, stupid, don't be a dewsh." I mean, "Hey, champ, you look sharp, did you just come from formation?"
One of the significant issues in the American military is the growing chasm between the population and the military. America's military was designed for citizen soldiers (much like we were designed for citizen legislators). We've moved rapidly over the last 50 years to insulate ourselves from the population, developing a caste system that has shown to be extremely dangerous to many, many civilizations throughout history.
In my opinion, wearing a uniform to a civilian event only serves to widen that chasm. The uniform was never meant for personal adornment or gain. It is a service uniform. Would you find it odd if a policeman or fireman came in their uniform? There really is no reason to wear a uniform to a civilian event except for personal gain or to establish a barrier between the military and the population we are designed to serve.
I'm not really interested in Joe being able to afford a suit. Joe is very well compensated, and if he doesn't have a suit he can buy a pair of slacks and a dress shirt from Walmart for about $40 - not that all suits are $1500 Ralph Lauren Purple Label. Joe was not issued his uniform to replace his civilian wardrobe, he was issued his uniform to conform to unity when at military functions.