Revisiting an earlier topic...
I am baffled by the number of people who argue thusly: "Substance A and Substance B are both dangerous. Yet Substance A is allowed and Substance B is prohibited. They should be treated equally!"
That's like saying that gasoline and plastic explosives are both dangerous; ergo, if private citizens are allowed to keep gasoline at home, then they should also be allowed to have plastic explosives. That's a ridiculous line of thought.