Of course if a druggie harms another, then he should be prosecuted. The issue is laws that prevent an adult from his private activity that does not interfere with another's freedom. Those kinds of laws are fundamentally unjust and create bigger problems than the activity itself.
Nice try, but the crowd on this board is immune to the message. Drugs kill, it's true. But so does suicide -- and it's still against the law, too.
Does anyone really refrain from committing suicide because it's illegal?
Prohibition and drugs have nothing in common.
Alcohol has been a foundation of and for Western Civilization for many thousands of years, in every way, that isn’t true of something like pot, which Western Civilization refused to adopt as an intoxicant during those thousands of years, although they interacted with, traded, traveled and fought the cultures that did use it, getting stoned on pot is a 1960s thing for “Western civilization”, alcohol has always been thoroughly incorporated into the white man’s culture and life, prohibition was a weird American second out of those thousands of years, one that sure would have surprised the founding generations, just about as much as them learning that Americans were taking on the drug of the Arabs.