So the question is, how are we able to justify this suicidal practice to ourselves?
We justify all our bad habits because they're addictions and it's human nature to justify our behavior, even when we know what we're doing is killing ourselves. I've never smoked a day in my life, but I had a food addiction that I simply couldn't break, even though I tried and tried and tried.....I finally had what's called a "gastroplasty", where they reduce the size of your stomach, but don't bypass anything and I'm down 50 lbs. I hated what my addiction was doing to me so I did what I had to to change it. I exercise 4-5 times per week too, which helps A LOT.
While it's up to each individual as to whether or not you want to stop smoking, you have to realize that with an addiction like smoking, it's affecting not only you, but others around you because they breathe in the smoke you're exhaling. If I were in a restaurant eating a piece of chocolate cake and I spewed half of it all over people at the next table, I don't think they'd appreciate it too much.
Any addiction is very difficult to break, and you have to WANT to quit. A close friend of mine, an ex-Dub, started smoking again last year after quitting 30 years ago. It's cost her big time. Not only is she coughing more now, but her kids (all Dubs) found out she was smoking and will no longer allow her to see her grandchildren. She's furious but she won't quit smoking. She views this as a power-struggle between her and the religion and she said to me "there's no way they're telling ME what I can and can't do!" I said to her "you raised your kids as Witnesses, so their reaction to your smoking cannot possibly surprise you."
While I know she's hurt that she can't see her grandchildren until she quits smoking, I view it that she's chosen cigarettes over her grandchildren---and she lived for those kids. I don't agree with what her kids have done, but unfortunately if we've got family in the Borg, what we do can still affect family ties.