I don't think anyone who's even briefly looked at the effects of different drug policies would disagree that harm minimisation is the most sensible policy, in terms of sensibleness/societal wellbeing/cost-effectiveness. It's just that people are ignorant, and politicians need to cater for that. It's the same with a lot of dumb policies e.g. climate change inaction, illegal immigration, lack of investment in infrastructure. Bleh.
Also, Portugal seems to be doing ok after drug decriminalisation.