You act as if CANCER is the ONLY disease smoking is responsible for.  In fact, smoking causes more deaths from cardiovascular disease and non-cancerous lung disease than it does from lung cancer.

 From the study you have just cited:  “Passive smoking has many downstream health effects—asthma, upper respiratory infections, other pulmonary diseases, cardiovascular disease—but only borderline increased risk of lung cancer,” said Patel. “The strongest reason to avoid passive cigarette smoke is to change societal behavior: to not live in a society where smoking is a norm.

And from the CDC:  

Exposure to secondhand smoke causes an estimated 41,000 deaths each year among adults in the United States:

Secondhand smoke causes 7,333 annual deaths from lung cancer.

Secondhand smoke causes 33,951 annual deaths from heart disease.

Secondhand smoke kills more Americans than ISIS.