Let me guess, a costume is anything you personally don't wear? Newflash pal, there is a practical purpose behind almost every article of clothing that I wear. If you want to talk about costuming, let's examine the necktie which serves no function whatsoever.
"Let me guess, a costume is anything you personally don't wear?"
Guess again.
"Newflash pal, there is a practical purpose behind almost every article of clothing that I wear."
Never having seen what you wear, I will not comment on that specifically. I will, however, make the general comment that there is practical, utilitarian motorcycling apparel and equipment that does not add up to an "outlaw biker" costume.
"If you want to talk about costuming, let's examine the necktie which serves no function whatsoever."
Okay. That is a costume that says, "I do feel morally constrained by society's customs and laws. I will not stomp you, shoot you, or rape your daughter. I accept my responsibilities as a member of society, and most likely have a productive job. Further, I have enough respect for you to communicate all that by wearing this costume."