If we really are thinking, we'll severely curtail or ban destructive substances, especially when we have ample evidence of their destructive natures.
Like alcohol.
And tobacco.
And sugary drinks.
And bacon.
Stop making invalid comparisons. You only look stupid doing so.
Substances which are dangerously mind- and behavior-altering are not even in the same universe as certain food items.
Regardless, my original post only posits that if you makes something legal that was previous illegal with high consequences as a cost, more people will indulge in it, not fewer as some brain-dead libertarians like to claim. That’s just basic economics. You lower the cost of an item, more is sold.
And yes, there will always be an illegitimate market for it. It doesn’t solve that problem.