So perhaps you should teach them not to use drugs instead of trying to control what other people are allowed to put into their own bodies.

It really should be both.

Disregarding the fact that opioids are still illegal without a prescription (much like meth, and marijuana) there's plenty of articles that show that legalizing marijuana has lowered opioid use in those states.

That's the opposite of what studies on drugs use/availability say.

People in the Netherlands don't get stoned everyday just because they can.