The difference between smoke, beer, and fast food is that smoke hurts everybody in the direct vicinity of the smoker. My dad drinks wine and beer. I might not like the smell, but I can deal with it because that smell isn't going to give me cancer. If I go in a McDonald's and am surrounded by the scent of grease, I'm not gonna get cancer. If second hand smoke isn't as dangerous as originally thought, that doesn't change the fact that it's still dangerous.
People downtalk smokers because it's not fair for you to ask them to risk their health to spare your feelings. What you do with your body isn't any of my business, and I agree whole-heartedly, but if you're smoking and that smoke gets near enough to me to impact my health, you've made it my business.
I live in a place where people smoke. Believe me, I'd love to leave, but I can't. I go to the park; there's a smoker. I go to town; there's a smoker. I won't do anything because it's a public space which allows that, but I'll be damned if I don't complain when a smoker hurts my health. I have just as much a right to not inhale smoke as they do choosing to.