Normally I'd agree, but cigarettes in particular are a product that is designed to be as addictive as possible with a laundry list of negative health impacts and virtually zero positive ones. Combine that with the fact that you aren't just putting it in your body but the body of anyone within breathing distance of you, there's a strong case to be made for banning them outright.
Put it another way, if cigarettes are legal then marijuana, LSD, MDMA, and a whole host of other drugs should be legal too.