(Wanting to keep names out of it makes every sense and noone can be criticised for that, but it gets confusing with two GUESTs without temporary handles posting to say how they disagree with each other.)

The gateway drugs for the vast majority of people are tobacco and alcohol, probably smoked and drunk at an age where that too is forbidden. That is where people learn that it is possible to change the way you feel by ingesting substances. Or perhaps even earlier, with tea and coffee. If cannabis didn't exist, there is no reason to suppose that any fewer people would move on from tobacco, alcohol and caffeine to heroin.

What makes heroin so devastating to lives isn't the drug itself, it's the clumsy and brutal way in which society tries so ineffectively to crack down on it. Where it is possible for people addicted to the drug to have it made available in a legal way, subject to quality control and proper pharmacological standards, addicts can and do lead good lives, and carry out socially useful jobs. And they even give it up, because for some people it is the illegality and the lifestyle that goes with it that is a large part of the attraction.