It's a product of American gun laws which used arbitrary visual cues to determine what an assault rifle was or wasn't. There's certainly some kernel of truth that if you're going to be banning things based on constituent parts, you probably aught to have basic familiarity with them. The law was incredibly stupid (a pistol grip makes the gun dangerous because you can shoot it from the hip! this is disproven by picking up a rifle with a pistol grip and trying to hold it at hip level to shoot) and the gun pedants have never recovered from it.
It's a product of American gun laws which used arbitrary visual cues to determine what an assault rifle was or wasn't. There's certainly some kernel of truth that if you're going to be banning things based on constituent parts, you probably aught to have basic familiarity with them. The law was incredibly stupid (a pistol grip makes the gun dangerous because you can shoot it from the hip! this is disproven by picking up a rifle with a pistol grip and trying to hold it at hip level to shoot) and the gun pedants have never recovered from it.