Medical Marijuana

I don't get why there's such a debate over medical marijuana. I get personal use debate, but medically makes no sense to me. If its so easily proven that marijuana does help certain people with certain problems then why not let them use it. You can read and watch debates about this stuff and all the negative are always irrelevant. Nothing they say stand ups to the fact that marijuana helps these people. People put their faith in our government to make the right decisions, but our own government has no faith in us. Marijuana should be available anywhere and everywhere to some one who needs it. There's nothing you can say to negate the fact that medical marijuana helps sick people. Who are you to tell them they can't have it?