Most (not all) of the harm attributed to drugs is due more to prohibition than anything to do with the drug. Overdoses often happen because with street drugs you don't know how strong the stuff is. It's often diluted with bad stuff.
We saw the same thing with alcohol prohibition. It's main effect was to increase use (watch the very good Ken Burns documentary) and get the Mafia started in this country. It also killed and maimed lots of people who got bad booze. Some of it was poisoned by our own government. "That'll teach 'em a lesson."
As long as you don't drive while you're impaired it's not really any of my business what you imbibe, ingest, or inhale. But some people live in constant fear that somebody, somewhere, is having a good time.