The difference is that nicotine harms only the physical health whilst alcohol and drugs including pot have behaviour-alterating and brain-damaging consequences. Talk to drug experts not pot-promoting apologists.
Did you ever try pot yourself? I did! So I can't take it too serious if you write about things you don't know. In my opinion you will do a great disservice on young people if you over-dramatize the negative side-effects of Marihuana because then some of them will believe really dangerous drugs like Heroin, Cocaine, Crack and Meth are not too dangerous also.
The majority of studies analyzing the long-term effects of cannabis products on consumers prove that it is not more dangerous than alcohol.
I live in Frankfurt/Germany, a city that is liberal towards the use of re-creational drugs and decriminalized it pretty much. People in Frankfurt have the right to possess 5 grams of Marihuana or Hash and the Police will let you walk away with it. I know clubs and bars where it is tolerated that people consume marihuana, almost everybody I know has experiences with smoking pot, and our society is still functioning pretty well. It's not considered a big deal.
Of course Cannabis is a drug and like every drug it can be dangerous and harmful. I don't want to downplay this. Drugs are nothing for children, adolescents and for people who are mentally fragile! This must be clear! Now you will probably say who knows who is mentally fragile and who will be able to cope with it. I don't know myself but drugs in Frankfurt are so ubiquitious the mentally fragile will get their drugs anyway. By partially legalizing soft drugs the state at least regained a little bit of control over the illegal market back.
If you write all drugs, including alcohol and nicotine are dangerous and should be prohibited than I can comprehend that, but a society without the right for rush would be a pretty boring one. This is my point of view. ;-)