So we should make illegal for adults everything we don't want kids doing? Alcohol? Tobacco? Sex?
Alcohol and tobacco have been with us for centuries. I don’t think you can compare them to all of the substances available now.
I’m never exactly sure what people mean by ‘legalize and regulate’. But by what I perceive as the logical extension of your stance, we should ‘legalize and regulate’ everything possible, and make it all available to all ‘adults’.
It seems to me that we should make wise judgments about individual things, according to where we currently stand as a society, and whether we are in a position to deal appropriately with the possible consequences. And I think we’ve always done that.