The anti-smoking crowd is just another interest group that found its home in the Democrat party, so Obama and the other Dems are obligated to do their bidding. If they can stick it to 20% of the population, who cares? Most of those 20% are poor and minorities who aren't going to vote Republican anyway, so why not walk all over them?
If smokers had been organized 30+ years ago, with something resembling the NRA, none of this would be happening. But they're not organized, they've been made to feel ashamed (and thus guilty) for their habit, and there's almost nobody to come to their defense.