People still drink, indulge in unhealthy food, and jump out of perfectly good airplanes knowing how harmful those can be as well, it's all about perspective and what you truly care about in life and what you hold close. Unfortunately nicotine is addictive, but fortunately we're living in the modern day & age where we can now have significant alternatives to smoking and getting our caffeine... oops i mean nicotine fix. It's really up to the public to decide how they want to receive their products, via tobacco filled cigarettes, vapor products & electronic cigarettes, patches, gum etc etc. The trick is to help these alternatives have a fighting chance against the larger companies who have been around for a good while and have the reserves to push out the little guys.
I digress, Nimoy will be missed, and hopefully there are a few fans of his out there who followed in his foot steps of quitting analog cigarettes for good, or found a helpful alternative.
Because sometimes the needs of the one, outweigh the needs of the many.