If one is illegal - one that is far less dangerous - then why shouldn't the other be illegal? Or, more to the point: if one is legal, then why shouldn't the other, far less dangerous one be so too?
They should be legal because people should be allowed to put whatever they want into their bodies, but they should stop moving the goalposts when it comes to different substances.
Urban Myth!! Heroin is not only more addictive, it is also a mind - altering drug... How many prosecutions and crimes are committed because someone needs to meet their need for a Cigarette? Compare that with the crimes committed due to people needing a Heroin Fix!!! If there was any truth in Nicotine being more addictive than Heroin then do you not think that it would be used as a Defense in Criminal Trials??
As a nicotine addict myself, I would have no problems with a total Cigarette ban, I would get on with life, probably a bit irritably at the start, but I know I would be benefitting myself in the long run, and those around me. Thereby hangs the difference... a nicotine addict does not lose all sense of reality