because the CIA and DEA smuggle drugs themselves, and if it were legal, they'd not be the biggest drug dealers in America. They trade weapons for cocaine, heroin, cannabis, and other drugs. This is well documented, look it up on google: the CIA and the war on drugs. It's also illegal because people in the past have used cannabis to blame things on society in a very ignorant way, to further their advances in their careers. If you don't believe me, look it up yourselves. The war on drugs is not a war on drugs, it's totally fake. Just remember that our friends over in the CIA and DEA are the ones who are polluting our cities with drugs like heroin.