Why are you so certain that drug legalization will increase the incidence of drug abuse, abused/abandoned minors, and drug-related crime?
Why do you completely ignore the constitutionality issue?
"Harm" includes taking my tax dollars to pay for someone's aftermath of "recreation." There's enough of that happening now.
"Harm" also includes taking my tax dollars to pay for harassment and incarceration of many harmless drug users.
With the billions of dollars we wouldn't be spending on the drug war, we could do a lot to compensate citizens for any "harm" caused indirectly by legal drugs.