I used to think that but I don’t anymore. Not having your shut together and not being a contributing member of society hurts others, so drugs aren’t harmless. Drug users are people’s kids, parents, etc., who have responsibilities and often can’t meet them because of their drug use and that hurts people. And the ship has probably sailed on letting drug users die in the street if they need help so the cost of welfare and services are also a burden.

The real question to me is whether making drugs illegal actually creates more burdens than it avoids. I suspect the answer is that if the culture condones drug use, you’ve already lost that battle and making it illegal is pointless. Laws should help reinforce norms. If the norms have broken down, enforcement of the law needs to be too coercive to be feasible. For example divorce also imposes tremendous social costs, but we probably can’t fix that by repealing no-fault divorce laws.