Probably because Joe knows absolutely nothing about firearms.
If/when/or 9 mm gas operated semi-auto pistols are banned, can revolvers be far behind?
My S&W 357 Magnum is a 6 shot mechanical semi-automatic hand gun, and while it is not quite as fast as a gas operated semi, using auto loaders, I can put plenty of rounds down range and it is quite lethal.
First they came for the Jews.