Why should we think that government officials are better at acting “rationally” than those they regulate? Even if we were to concede that smoking deserves to be restricted, why should we think the government can do it in a reasonable way?
It is not a conclusive proof of a doctrine's correctness that its adversaries use the police, the hangman, and violent mobs to fight it. But it is a proof of the fact that those taking recourse to violent oppression are convinced of the untenability of their own doctrines.
Politicians are very proud when they can say a proposed program is "paid for." But this only means they've identified their intended victims ahead of time. Naming who will be plundered does not justify plunder.