To get things back on topic...
They're both equally ignorant. But there are more causes for cancer than cigarettes. There are still surely many unknown carcinogens that we're exposed to every day, and cancer that develops without an outside factor. By avoiding cigarettes and everything else that we know to avoid, we can stack the deck against getting cancer, but we can't prevent it. We can prevent AIDS.
I apologize for trying to start crap. I never imagined this to be as one-sided as it ended up being.