Interesting thread.
Dryfly's post is to my mind a balanced statement of how things could be.
My addition will be from another, different, perspective. I've been lucky to have worked in many places in the world.
One of these was Mexico, where it went from being a nice place to being a deadly place purely because of the switch over to cash-crop pot. One week we were working happily in the valleys and hills of the Sierra Madre with our
burros the next we were stopped and hassled by paramilitary forces wielding MP5's in our faces. Twenty-odd years ago, admittedly. Now it verges on a narco-state where many die, because of the huge market on it's doorstep.
Another was a small S American country on the Columbia-Europe route. The kind of place where planes landed on roads in the jungle at night and if you were passing at the wrong time you were in mortal danger.
I am slightly of a different view. All my life I've been averse to pushers and dealers, and some of the reasons are clear from this thread.
IMHO It's making a profit, and ripping folk off that causes the issues, just like Prohibition lead to the American way and Maffiosi, in comparison to the drunken louts on a Feet Neet typifying Yorkshire.
It's also true that some people appear more susceptible to addiction, and sadly that is just human nature. But failing the Darwin awards can often be facilitated by the pushers and dealers
As with many things, everyone tends to see the things near them, the individuals who go off the rails, etc. and that paints their world view. But it's not a proper world view. It doesn't acknowledge the background, the many individuals, communities and even countries that have been degraded and destroyed by illegal drug trade.
Legalise it now. IMHO.
PS Of course,

I have never inhaled, just like I never accepted a funny shiny leaf from my Carib field assistants, that helped with the pain of lugging 30kg packs through 35-degree heat and 90% humidity...
.