Hunter Bob is required by law to wear orange. It might keep him from being shot by a negligent hunter in an uncontrolled situation. If there is a real need for a vest on a range, there are serious problems with range management. There are demonstrable reasons for eye and hearing protection which are unrelated to carelessness, negligence, etc.
Camouflage, tactical gear, etc. may be useful under certain circumstances. If someone wants to dress up, I suppose that is their business. Different people like to dress up in all sorts of outfits. Wearing a vest at an organized shooting event could be sending a message. It could imply that the wearer thinks that the range is not a safe place for a recreational activity. There have been discussions here about image and the public perception of the shooting sports.