>Addiction is a dangerous disease and we should protect everyone from falling into that trap and harming themselves and others around them.

Addiction isn't some disease that can strike randomly, the science shows that people who are already unhappy/unsatisfied/deprived are much more likely to succumb to addiction. Addressing the societal problems behind that would go a long way towards eliminating problematic addiction, and conversely banning all narcotic substances wouldn't stop those people from finding other ways to harm themselves, like alcohol, gambling or overeating to fill the emptiness inside.