It's not a matter of personal responsibility, but of statistics. If you have a population of a few dozen million which is targeted by an addictive product which is heavily marketed a proportion of them will end up using that product for a long time.

And if said product is harmful, one has a public health issue on their hands. The sad thing is that we've already been on a similar path once with normal cigarettes: the lying, deceitful marketing, the people dying in droves, addicts proudly proclaiming their rights to self-determination.