That's not quite the statement
"Take for example the statement that "smokers and topers" more than pay for their treatment by paying taxes on their favourite poisons.... ahem...."
That's not quite what is being said, that fags taxes pay for the treatment of fag related diseases (although every claim about the cost of treating smokers on the NHS is in fact lower than the amount of fag taxes collected).
Rather, the claim is that the NHS treats people their whole lives. The costs of treating a smoker, fattie or boozer are lower, on that lifetime basis, than someone "healthy". The reduction in the number of years of treatment costs is greater than any specific costs associated with treating those diseases.
I've linked to a "real" (ie, peer reviewed etc) paper making the point and there's many more like it out there. It's not a controversial point in fact. Someone who pops their clogs at 65 from lung cancer costs the NHS less on a lifetime basis than someone who is still getting hip replacements at 80. And we all end up getting terminal care for something because we all do die.