I mean if we deny smokers medical services we might as well deny obese people and people with a sedentary lifestyle and so on and so on. Wouldn't it be better if we could just do what we want to do without anyone interfering at all?
It would be if the actions of certain sections of the population didn't have an economic impact borne by others. That's where most of the controversy lies. We enjoy our wee vices and the economic costs, estimates are in the tens of billions annually in the US alone, are paid for by the population as a whole.
It's not realistic to expect every person with an addiction to be able to give up that addiction. Nature is in the way of that. So either restrict the activity, or make those who engage in it cover the cost, or be denied access to services.
If the economic cost, in terms of health and productivity is 3 times the value of business generated by that activity, then a 300% tax would be entirely justified, provided that the revenue from those taxes was limited by law to subsidizing that economic cost to the rest of the population, with suitable criminal penalties imposed on those who steal from this revenue.