The BMI is just a very rough guideline....it does not take into account body types, percentage of body fat, etc...
It is unreasonable to assume that all people the same height should weigh the same....plus (just to illustrate how weird it can be)....When Arnold Schwarzenegger (sorry if I misspeled his name lol) was Mr. Universe, according to the BMI, he was OBESE! LMAO

Butterfly, you do have a point, but you forget to mention that smokers are causing health related issues to the whole society and not just themselves through second hand smoke (whereas the other health sinners are only harming themselves).

Stay safe all.

Perfection does not exist. The question therefore, is: what level of imperfection are we willing to settle for?