What evidence do you have that this isn't true? It's not really a falsifiable position (since nature vs nurture is hard to show) and free will hard to measure.
To me, it simply seems more convenient for the audience to believe free will doesn't exist and addition is genetic.
There is plenty out there [0]. Certain substances are at a baseline and without question addictive for humans, do enough of it and anyone can become an addict regardless of free will. Genetics play a role in susceptibility and level of dependence, as do other factors like underlying mental illness. If you ever see a full blown alcoholic going through withdrawals [1] it becomes clear that physical substance addiction is very much a real thing.
To me, it simply seems more convenient for the audience to believe free will doesn't exist and addition is genetic.