I think comparing cigarettes and vape devices is like comparing apples to oranges, only thing in common is the nicotine (If you even vape nicotine, many people don't.)
If your gonna compare it to cigarettes might as well compare it to caffeine, everyday pain relievers, fatty foods, sugar, salt, sleeping aids, lead fishing weights, yadda yadda... They all are bad for you or "kill" you as some of you call it.
I never smoked cigarettes, I've tried it but never got to the point I was addicted then I picked up vaping when I turned 18 and it was legal for me... I didn't use nicotine starting out I only used zero nic juices, now I switch back and forth between zero and 3ml nicotine (the lowest dosage most companies make) because I like the buzz I get from nicotine and it gets me a lot of the same effects I got from caffeine which I recently stopped using as much because I want to get off soda.