Some of the nicest people wear cammies because they spent their expensive chino money on another case of ammo. Some of the biggest pricks in the world have been known to wear a suit on occasion. Heck, Hitler was quite the snappy dresser. Want him at your range?
Gun owners are all types and stripes. I have seen every demographic of dress demonstrate amazingly good and appallingly dangerous gun handling. The guy with the baggy pants nose ring and gold chains is just as much a gun owner as is the cammo wearing fella or you or I. Not everyone can look like they just stepped out of suburbia and be "normal" It is up to the individual to make the choice whether or not they will be responsible gun owners and further will they clean up for the camera. What they wear during their personal recreation time at the range is their business.