First of all, regarding drug use, unless the dealer ties someone down and injects them against their will, it is the drug USER who destroys their life, not the dealer.
Violent crime associated with drug dealing is a function of it being a black market, not the drug itself. We don't have drive-by shootings in front of liquor stores nowadays, but we did during prohibition.
And third, alcohol causes far more harm than all other drugs combined, except perhaps health problems from cigarettes. But yet you don't seem willing to discuss it here.
What does alcohol and cigarettes have to do with the discussion about illegal recreational drugs? Unless you're saying that their use would decrease if we legalized drugs.
Is that what you're saying?