Why do people think that marijuana is so bad!!?

All of the stuff we hear about marijuana is mostly untrue. It does not make you stupid and it does not alter your decision making. And it is becoming legal in states for medical reasons. So why does the government insist that it is bad and why are people brainwashed into thinking the same thing. It has many healing properties and is used for patients with cancer, AIDS, glaucoma, anorexia, it is a stress reliever, and relieves stress. Studies in universities in California and other states including Michigan and Maryland have preformed studies on thousands of users and have concluded that even long term marijuana use does not cause brain damage and if damage is caused it is minimal. Im beginning to think that the government doesnt want us to have marijuana because the Federal Drug Administration makes billions of dollars every year making synthetic unatural drugs that treat the same things that marijuana can treat. It is an issue of money and lobbiests. What do you think about the issue?