The origins of the right to bear arms goes back to 12th century England when King Henry II obligated all freemen to bear arms for public defense.
While some states require a permit to carry a concealed firearm, open carry has been legal everywhere but in the most liberal cities since ratification in 1791.
That being said, I agree with the NRA statement; "It's downright weird and certainly not a practical way to go normally about your business. Using guns merely to draw attention to yourself in public not only defies common sense, it shows a lack of consideration and manners."
Kudos to the NRA for admonishing some foolhardy members.