Taxes of the sort on alcohol/tobacco are called 'sin' taxes and originally were designed to curtail consumption.

The tobacco firms settled with the government to save money in the long run (due to promises of avoiding future liability). All kinds of civil suits are settled for less money if threat of larger penalties in the future are real and substantial.

The tobacco companies are accused of spiking cigarettes to add more nicotine. Tobacco naturally has nicotine in it.

Furthermore, it was the government who originally got most people hooked on cigarettes (free ones for soldiers, etc. during the wars). At that time I doubt the science existed to know the real dangers.

Finally, nobody sticks a gun to anyone's head and forces them to start smoking. So why should the government pick up the tab? Does the government have liability for drinking problems, gambling, and other forms of addiction?