Paternalism.

Users of Krokodil are highly likely to die as the result of their use, often within a year of starting (a few have made it as long as five, although this is very rare), and the few addicts who make it into rehab face around a month of severe withdrawal symptoms; the pain is so horrific that people frequently need to be put in an induced coma.

-Krokodil on rationalwiki

If you knew someone was going to try krokodil, would you stop them?

Would you support a law to stop them?

I feel like the schizophrenic opinions that arise around paternalism here owe to claims that it is politics. I think that's a bit of a cop-out personally.

Second level consequentialism

Does smoking cost as much as it makes for the Treasury?. Just one of many high quality articles on full fact. What, if anything, can they do better?

Given that smoking costs the legitimate decision makers more ('bad for the economy'') and hurts the population ('bad for society'), is that sufficient reason to intervene in the market?

Why even think through such things! We ought we pander to those who don't understand these issues and keep away, since if we didn't understand them intervention in the market sounds pretty scary?