E-O-M, lives are shattered as well by alchohol and gambling, many more in numbers. That is the point. Alchohol is toxic, and is progressive, the user drinks more till they are really causing themselves severe physical damage. Gambling I have seen people sent to jail over fraud caused by.
Cannabis, properly dosed and regulated is used overall less by volume and so is less toxic, or on the plus side has medical benefits.
Please tell more about the lives shattered you have seen.