There are zero laws against the design, manufacture, sale, or possession of cars with spinning blades and/or flamethrowers.

Such laws attach to the human operators of such cars, if they recklessly endanger others by driving them on shared, public roads.

But they're perfectly legal to own (and operate off-road). And, there's no technical barrier stopping people from illegally driving them on public roads: just fear of laws.

(There's entire subcultures of people who modify cars to do insanely dangerous things, on private race tracks. Perfectly legal).

If we were to apply Amodei's safety standard to cars—do they have the theoretical risk of killing over 50 people—well, cars empirically kill tens of thousands of people in the US annually, so we'd have to categorically ban them. That standard is bad-faith and absurd.