It is a mental addiction though. Take it away from them and sure they'll want it. Do they have violent reactions? Well maybe if they rob a bank to get money to buy weed.
Alcohol is legal and it has it's problems. At least you are not supporting Cartels, organized crime by buying alcohol. You are also not a criminal for doing so.
Seems fair enough to me for MJ to be treated the same. Get the criminal element out of there. It ain't going to be perfect, but it's better than what we are wasting on regulating it as an illegal drug.