Lynne - please do not class all drug addicted people as murderers, thieves, etc. My daughter became addicted to codeine when she was given it in hospital when she was in agony following a botched operation. The biggest category of addicts are hooked on prescribed drugs, doled by doctors in the form of tranquillisers. You seem to have a very limited view of addicts - how many have you known, apart from smokers?
And I am afraid many smokers are harming others - have you seen the new adverts about how much of smoke is not visible? I very much welcomed the ban on smoking in enclosed, public places -why should I have to breathe air which is polluted by somebody else's habit, and have my clothes permeated with the noxious smell?
When anybody is challenged on any form of addiction, including smoking, the response is usually one of denial, anger, or counter-accusation.
I believe cannabis is psychologically addictive - users crave the sense of well-being it gives them.