This video claims that this is a "historical usage" that was deprecated in 1917. As a matter of historical fact I have no clue if this is true. I wasn't alive in 1917 though so I suspect this notation was alive and well up until at least 2001.

The example they give is pretty good and exactly explains how I think about it.

6 \div 2(1 + 2) \\x \div y(j + k) \\\frac{x}{y(j + k)} \Leftrightarrow x/(y(j+k))
x = 6 \div 2(1 + 2) \\x = 6 \div 2 \cdot (1 + 2) \\x = \frac{6}{2} \cdot (1 + 2) \\x = 3 \cdot (1 + 2) \\x = 3 \cdot 3 \\x = 9

Added what appear to be the original form of the problem.

x = 6 \div 2(1 + 2) \\x = \frac{6}{2(1 + 2)} \\x = \frac{6}{2 + 4} \\x = \frac{6}{6} \\x = 1 \\y = 6 \div 2(1 + 2) \\y = \frac{6}{2(1 + 2)} \\y = \frac{2 \cdot 3}{2(1 + 2)} \\y = \frac{2 (1 + 2)}{2(1 + 2)} \\y = 1 \\z = 6/2 \space \space (1 + 2) \\z = \frac{6}{2}(1 + 2) \\z = \frac{\tfrac{6}{2}}{\tfrac{12}{4}} \\z = \frac{3}{3} \\z = 1

I'm a sucker for those math problems that go around Facebook.

x = 6 \div 2(1 + 2) \\ x = \frac{6}{2(1 + 2)} \\ x = \frac{6}{2 + 4} \\ x = \frac{6}{6} \\ x = 1 \\ y = 6 \div 2(1 + 2) \\ y = \frac{6}{2(1 + 2)} \\ y = \frac{2 \cdot 3}{2(1 + 2)} \\ y = \frac{2 (1 + 2)}{2(1 + 2)} \\ y = 1

Inside of the room.

Outside of the room.

The best argument I've seen recently for banning this style of weapon comes from the corporations involved. I'm linking to a video where they show off some nonsense that actually clarified the other side's arguments: They're lying about what their weapons even are and how people should use them. See the video for this "Pistol Stabilizing Brace" where you see a guy firing what is obviously a small rifle in some sort of nonsense way to make it not illegal to call that thing a pistol.

I spent my whole life being told by conservatives that they don't want to think beyond "If it looks like a duck and quacks like a duck it must be a duck" and then they pretend this stupid shit looks fine to them.