I agree that smoking is bad for you, having quit myself - but the idea of outlawing a plant / prohibiting humans who just happened to be born in one specific part of the world from burning it and inhaling the produced smoke just goes against my views on ethics.
Instead, why don't we fix the real problems? How about getting rid of capitalism, and thus the profit incentive to sell addictive substances for a huge markup? How about we fix this broken society that keeps pushing more and more people towards drugs such as nicotine, the tiny escape, and the little bit of stress relief they provide?
Drugs, from cigarettes to meth, are not the problem..
They're just a symptom.
The war on drugs is nothing more than an effort to sweep the real problems under the rug, and nothing less than coordinated violence targeted at people who are already suffering.