It’s really very simple.
If you smoke long enough it will kill you through cancer, heart disease or the slow destruction of your lungs.
Tobacco is one of the most addictive drugs in the world. Only meth can be shown to hook you faster and more completely.
Most people have known – or should have known – this since the early 1960s and the original Surgeon General’s Report on Smoking. The tobacco companies knew this in the 1950s but kept it a secret in order to make money. Their own documents show this.
I suppose it’s alright to smoke on Purim, so long as it’s just once a year, the same way it’s alright to shoot up heroin or smoke crack on Purim, so long as it’s just once a year :-