Guess it all depends on how literal you want to be with your verbs. On a strong technical level they’re vaporizing rather than smoking, but I don’t see a point in quibbling. In the community “quitting smoking” means quitting nicotine, nobody congratulates anybody for quitting smoking if they’re method is switching to chew, still on the nic is still on the nic.
I’m a member of the having quit smoking cigs community you speak of. 20+ years. No e cigs.
We long time members of that community didnt have the option of ecigs, so I guess what I’m suggesting is that maybe the terms of the discussion have changed a bit. You can quit using the cancer sticks but can continue to feed your craving. An addict but not a smoker.