As a reformed heavy-smoker who also smoked in a room full of computers, I'll call your bull... er, bluff on this one. I generally take apart my computers once a year or so to blow out the dust and remove the cat fur that inevitably clogs the intakes. I've never had an issue with tar on heatsinks, nor premature failure of components. Some of my machines were in constant use for up to a decade before finally being retired.
Non-smokers whining about the smell of old tobacco is one thing, but when we resort to lies to "prove" a point, there is no argument.