It's just an example...although extreme. I have worked on PCs that the moment I turned them on they blew out a cloud of cigarette smelling smoke from the back of the PSU. Opening the case up I was exposed to serious disgusting stink of smoke. Computers use fans and have vents in the front. They will draw in that cigarette smoke and coat the internals with it.
Here, look at this:
http://www.smokerslungs.com
That is the same disgusting garbage that is on the inside of a smoker's PC. Although those lungs are from YEARS of smoking it shows just how vile smoking is and what it does to EVERYTHING exposed to it.
It's disgusting and I refuse to ever be exposed to it if I can help it. I don't like Apple as a company but I completely support refusing to touch a PC that has been so smoke filled that it reeks of cigarettes.