Not everybody smokes.
Deeply inhaling superheated chemicals like hydrogen cyanide, ammonia, numerous carcinogenic hydrocarbons and whatever random chemicals and pesticides where on the plant is not the healthiest thing to do.
This toxic chemical soup is deeply inhaled and expands in lung tissue at temperatures exceeding 1,600°F. Cannabinoids are not, by any stretch of the imagination, the only chemicals inhaled in marijuana smoke.
Smoking marijuana is a personal choice, but not one without health consequences.