About ten years back, I remember an article saying that incense was carcinogenic. So, like anything, in lies a hypocracy for those that think incense is healthier. But, it could just also be that some folks have a repulsion to tobacco in general. When I was first quitting cigarettes, any tobacco smoke repulsed me. But, I know/knew it was just in my brain, because of the fight going on in there.
My wife was a tobacco Nazi when I first met her, and I was fighting my own addiction. Her father died of lung cancer. She would gag at any tobacco smell, so it kept me on my toes when lying about whether so had cheated. But, with years of bringing her into my world of pipes, and encouraging her in listening to the PM radio show, pipe shows, goon to the Briary with me, she came over to the dark side. She doesn't smoke, but she no longer bawks at any tobacco smells. Well, except for cigars and cigarettes. She still doesn't like it when I fire up a stogie.
But, I think it's just psychosomatic.