Well considering that both of my parents and a bunch of direct family members all got sucked in, and I myself consistently struggle against an addictive personality (see aforementioned near gambling hole), I'd wager whatever genetic component exists is likely present.

I'm not "immune" due to being unable to be addicted, I'm immune because I never fucking put myself in a position where I begin to consume in the first place. You don't just wake up addicted to alcohol or heroin by accident, you have to actually use it in some way. And for those with legitimate uses like pain killers, you don't become addicted due to using it once, you begin down a path you need to watch yourself from going down through personal discipline.

Nothing you've said is wrong, but it just jumps over the most key component. Personal agency. Its not a random tragedy of life, its a deliberate choice made at some point that spiraled out of control. Even you yourself weaseled in the phrase "using the first time" as if its just a thing that happens through magic and chance.

I won't waste effort looking down on those who are mostly only hurting themselves, like a smoker who keeps that away from his family. But I won't offer them any sympathy either when their consequences come.