Earlier quoted context omitted.
With the welfare state that exists, a common argument is that people that destroy their bodies or brains are a burden on "society".
I sincerely think that even if all drugs were legal, the rate of consumption wouldn't necessarily increase much. "People who take drugs "don't give a damn if they're legal, generally speaking.
Prohibition has become known as a failure because there was still a vibrant underground alcohol trade, but it didn’t mean that everyone continued drinking at the same rate. It really did reduce alcohol consumption.