A serious attempt to ban harmful substances would not necessarily start with rat poison because while rat poison is more harmful than other substances, it’s less harmful relative to how people use it. The fact that eating rat poison causes more damage to you than smoking weed is irrelevant; eating rat poison is an unusual use case for rat poison, but smoking is a typical use case for marijuana.
(Responding to old post.)
A serious attempt to ban harmful substances would not necessarily start with rat poison because while rat poison is more harmful than other substances, it’s less harmful relative to how people use it. The fact that eating rat poison causes more damage to you than smoking weed is irrelevant; eating rat poison is an unusual use case for rat poison, but smoking is a typical use case for marijuana.