Some follow-up thoughts --
Most anti-smokers accept carcinogens from other sources.
Consider candles. Most modern candles are made of paraffin wax -- a petroleum product -- and they release chemicals such as toluene into your home. Candles deposit so much soot that homes which burn them heavily have attempted (unsuccessfully) to file insurance claims over the damage. So, it's interesting to consider that soot is significantly carcinogenic and linked to the risk of cancer.
Woodsmoke (as from campfires or woodstoves) contains, according to one study, "much higher" levels of PAHs than vehicle exhaust does, and a "higher mutagenic and carcinogenic potential" than traffic exhaust. Besides PAHs, woodsmoke contains high levels of dioxins, benzene, and aldehydes. In any case, one Swedish study found that homes which heat by woodstove have approximately 4x the PAH cancer potency of homes which heat otherwise.
Nitrate cured meats form N-nitroso compounds (a carcinogen), and smoked meats form polycyclic aromatic hydrocarbons (a carcinogen). Processed meats as a category have a statistically significant correlation to colorectal, stomach, and breast cancers. Cooking any meat at high heat (as in grilling or pan-frying) produces polycyclic aromatic hydrocarbons and heterocyclic amines (carcinogens) linked to cancer. Starchy foods cooked at high temperature (french fries, potato chips, etc.) form acrylamide (a carcinogen) which damages DNA, induces cell death, and leads to oxidative stress which increases the risk of cancer.
But very few people consider others to be morally suspect for accepting some carcinogenic risk in burning candles, heating with a woodstove, or eating grilled meats.
In general, people seem to have strongly yet inconsistently held opinions about the ethics of risk.
A 1992 Royal Society report, "Risk: Analysis, Perception and Management," charted number of deaths per hundred million hours spent on various activities. Smoking clocked in at 40, while travel by helicopter clocked in at 500, and rock climbing at 4,000. Society should therefore be 12x more upset at helicopter passengers and 100x more upset at rock climbers than at smokers, for their inadmissible irresponsibility.