I don't smoke and if the other guy dies, that's his right if he / she chooses to do so. Naturally, like everything else, it should be in the proper place, if such a place is provided for it. I can understand how smoking in a cabin can leave an unpleasant smoke odor for the next guests coming aboard.
I've never been too concerned about people smoking on their balconies --if a ship is moving at 18-20 knots, the breeze will dissipate the smoke before it has a chance to travel very far at all and it's not likely that everyone on one side of the ship would be on their balcony smoking at the same time to generate large amounts of smoke--but, as I said, I don't smoke so it doesn't matter to me.
I do find it rather funny that some people will complain about smelling smoke and investigate as to who may be taking a puff somewhere--then those same people will gorge themselves all week day and night on fat, grease, sweets, and drink several gallons of alcohol--all of which is much more harmful than getting a whiff of smoke now and then.
Just my 2 cents -- doesn't bother me one way or the other---happy sailing, happy eating and happy puffing to all !!