If you're saying it's tyranny to prevent people from taking actions, that the majority feel shouldn't be allowed, that drive up healthcare costs then that's one thing. However if your position on this is based on a liberal ideal of people being allowed to do what they want, then it should surely equally apply to the taxpayers (particularly if they are majority voters) who don't want to pay for the decisions of others. Either way that is government intervention restricting individuals freedom.

I think it's not right to say "the governments money" as if an administrative body that is beholden to the voters has true autonomy over how it's spent - that is the populations money and should be their choice on how it's spent. One can argue it's immoral to refuse migrants access to the country and healthcare but that isn't accepted as justification for open borders. I also don't understand, assuming cigarettes are some special case different than immigration where morality should trump democracy, why it's more valid to say this taxpayer control over how their money is spent should be restricted based on your moral judgement compared to someone else's moral judgement who's claim is cigarettes are immoral (for whatever their chosen reason).

The claim of smokers dying younger and therefore costing less is something I didn't consider and is an interesting point (that very well could prove true). But even if you discredit the taxpayer funded health argument, there's moral arguments around selling addictive substances, human pain caused by premature death and sickness etc. that could just as readily be made as any argument based around individual freedoms. Why should your claims on what's moral have precedence over someone else's?