Hating someone for smoking is the same as hating them for wearing certain clothes or having a certain hairstyle you don’t like. It’s their choice to smoke, and if it bothers you, simply avoid that behavior.
I’ve had plenty of friends who smoked. I liked them for who they were, and just didn’t stay around them when they smoked. I abhor the act of smoking and what it does to the environment, people who inhale the smoke second-hand, and the smokers’ own bodies. I try to deter people who are interested in starting smoking, and if I know smokers who want to quit, I give them all the encouragement and support I can muster. If the person is a grown adult who has no intention of quitting, arguing with them is pointless.
However, smoking around one’s own children and babies is absolutely unforgivable in my eyes. If I see someone I don’t know doing this I will immediately have a very negative opinion of them, and if I do know does it, I’ll be sure to make a comment.
Luckily, I’ve heard that smoking has decreased in a lot of industrial countries. I can’t wait for the day when the human race realizes how stupid it really is and finally stops for good. If that day ever comes, that is.