Do people become addicts because of moral failing? In some (many?) cases, yes. Not all, and not undeserving of treatment/help to recover in any case.
I don't know where I stand on the issue of incarcerating people for drug use. But on its face I am not opposed to putting people in jail for selling highly addictive substances to young kids. This is one issue I have with the pro-legalization theory. Alcohol absolutely destroys lives (my grandmother drank herself to death when my mom was 13 in order to have some mental escape from the physical abuse of my alcoholic grandfather). Prohibition didn't seem to work very well, but general acceptance also seems to be failing.
It's a complicated issue, and I don't know where I stand on every aspect of it. But on its face I don't think punishment and help are mutually exclusive. And the fear of punishment _can_ be an effective deterrent. (Education being, in my opinion, the best deterrent. I've never had a drop of alcohol both because of my religious beliefs and the growing understanding that I'm very likely a drunk trapped in a sober body.)
Then we are still not talking about the same kind of punishment. I refer more to "they did this to themselves and have it coming" types of attitudes, of the self-serving moral outrage kind[0]. Which is not the kind of "tough love" you are talking about.
[0] http://reason.com/blog/2017/03/01/moral-outrage-is-self-serv...