It is the medical establishment that has targeted smokers.
Is it targeting smokers when they point out that they've noticed that 90% of the people they see for lung cancer are smokers?
I would speculate that some of the processing chemicals and additives in factory cigarettes might depress the immune system among other things.
You're still back to the smoking being a cause for trouble - And if the processing chemicals and additives depress the immune system then there would be various other detectable effects, organic pipe/cigar smokers wouldn't be effected as much as their consumption would warrant, etc...
Oh yeah, and the cigarette companies WOULD deserve to be sued into non-existence for that. It's a mitigatable risk. Don't use those chemical processes to treat the tobacco then.