Why? Because there are already far too many laws. Freedom requires the absence of laws regulating personal behavior.
Consider Freedom of Speech. Everyone has a right to express their opinions. Others may disagree, They may even leave the vicinity to avoid hearing unwelcome opinions, but they cannot prohibit another's speech. All freedoms require a similar compromise. Don't want to breathe second-hand smoke? Don't frequent places where people are smoking. This means that non-smokers must compromise enough to allow smokers suitable places where they can comfortably indulge their habit. It's reasonable, in a closed-circuit air-conditioned building, to prohibit smoking indoors. However, non-smokers are not entitled to never catch an unwelcome whiff of someone else's smoke and so it is not reasonable to presume that non-smokers are also entitled to monopolize the outdoor environment. Smokers do have the freedom to engage in smoking, as they have for generations. Just as Freedom of Speech requires us to tolerate hearing unwelcome opinions, living in freedom requires that we find reasonable ways to accommodate people who wish to do things we don't like.
Unfortunately, if the trend continues, exactly like the War on Drugs, it won't be long before the intolerant majority starts filling our prisons with tobacco felons. Is that living in freedom?