It’s absurd to ban a plant.
The alcohol part of the question is the most easily answered: been there, done that.
I agree that banning marijuana is bad policy, but it’s absurd to argue that it’s absurd to ban a plant. That something is or isn’t a plant has nothing to do with whether it should be legalized, regulated, banned, etc.
Marijuana-being a plant- should be used for medical purposes. However, if it is banned-in terms of medical purposes-then alcohol should be banned as well, seeing as it is the most dangerous substance that exists.