Earlier quoted context omitted.
> Cocaine, ecstasy, heroin, etc. are much more profitable, and legalizing these would be socially irresponsible, if fiscally lucrative. Are you claiming that the benefits that we actually get from the current prohibitions are greater than the costs of those prohibitions? If so, that's not obviously true. After all, I can get all of those things without too much effort, so what is huge benefit of making them illegal?…
It's not obviously false either - it's at least arguably true. When I said fiscally lucrative, I was admitting there may be a certain profit to legalizing these substances. However, it's socially irresponsible. I don't think a society will function as well with a government making clearly adverse narcotics freely available because people want them.
How are they clearly adverse? Why was it not clear before the middle of the 20th century? Why is it not clear in other countries? Why was alcohol "clearly adverse" in the early 20th century in the US? What's the evidence that making drugs illegal has net benefits to society?
It is very, very expensive and unhealthy to lock up so many young people for drug offenses. Illegal drugs do a lot of harm, but so do alcohol, cigarettes and obesity. If narcotics were legal, we would sadly continue to lose good people to them. But the evidence from Portugal* suggests this would be not more than we already do. And we would lose far fewer people to prison, drug-related violence and the accidents and diseases due to the conditions associated with illegal drugs.
* http://www.time.com/time/health/article/0,8599,1893946,00.ht...
(edit: spelling and added link to article about Portugal's policy experiment)