It's also a matter of quality of life vs pure "life expectancy" being worth consideration. Dying unexpectedly, even in large numbers is unfortunate. But a majority of the population living lower quality lives for reasons which can be addressed is more of a priority.
And it could be that addressing the real health issues will also involve improving some of the issues which lead to early death.
For example, with alcohol, why is alcohol use high? Could it be somewhat due to the insane amount of advertising and promotion by the alcohol industry? Could it be because, as people's lives tend to be less happy or lower quality, they seek easy distraction and escape?
Same with cars; cities built for humans instead of for cars will mean less car deaths and healthier people.
I agree with what you're saying at the end of this comment: if your policy goal is to reduce the life expectancy gap, interventions in health care and nutrition aren't likely to pay off, but interventions in urban design or economic mobility (to combat the drugs and guns) likely will. Which is why, if you believe what this article is saying, you should probably flinch when people write long comments about potato chip advertising in response to it.
Indeed, I don't see an obvious solution other than through pain and suffering (where some number of generations get worse and worse until they reach a breaking point, and after the dust settles there might be a large mind shift).
People die all the time due to other people's choices of embracing drugs and using guns. In a car with someone who's afraid of being caught with a little cocaine? Getting shot by someone who can't aim? There, you're now a victim of drugs or guns without making a lifestyle choice.