Because smokers actually cost society less than non smokers. They die about 10 years sooner. http://www.huffingtonpost.com/2009/04/08/how-much-does-smoking-cos_n_184554.html/
That represents a big savings in social security and medicare no matter how you cut it. So arguing that smokers should pay more because they cost more is just another big lie. Gets tiresome doesn't it? By making smokers pariahs, no one minds if they are forced to pay a huge dishonest "health" tax on each pack, a burden that fast food afficionados bypass....pardon the pun. Smoking is a huge cash cow for both state and federal government. If people are growing and rolling their own that is a huge chunk of change they will be missing.
Big Pharma, Big Tobacco and Big Gummint will be coming after e-cigarettes soon too. Count on it. E-cigarettes are catching on and represent the fastest, easiest way to get off the cancer sticks. Too bad Big Pharma didn't think of them first because then they could have jacked the price through the roof and put them under patents and sold them as health care devices and had the FDA protect their profits on them. But they didn't. Screw them. The government is worried that e-cigs will cut into their tax revenue and the pharmaceutical companies are afraid they won't keep making billions on their cessation drugs that are dangerous and ineffective and nicotine replacement methods that don't work. And tobacco companies just want people to keep smoking because it is so damn cheap to make and the profits are so good.