Earlier quoted context omitted.
Legalization of what though? Opioids? The drug that kills tens of thousands of people in the US each year, which is almost immediately and very strongly addictive, and with which it is extremely easy to overdose? No thanks. That'd be extremely damaging to society, and it'd inevitably kill a bunch of people and affect an order of magnitude more through network effects.
Look at the reason why people use drugs. I am convinced happy people with fulfilling lives don't get addicted. Large scale substance abuse is IMO an indication something went very wrong in society.
Even if that were true, it would still be possible that it was true because the same innate features which incline toward addiction work against having a happy fulfilled life in the same external conditions that someone without those features would have a happy, fulfilled life.