What if God sprang from the minds of humans? I would rather live in a society people don't kill each other because they know it's wrong rather than one where they are just afraid they will burn in hell. If your goodness is motivated from fear then how good are you? What about when no one is looking?
People who don't believe in God aren't the ones running around killing people generally. It's the believers that you have to worry about. I have a set of morals and I am bound to them because I believe in them. I didn't get them from God, I came by them through thought and reflection on what it means to be a member of society and the responsibilities inherent in that. I can do the right thing and know what the right thing is without God making me.
Tell that shit to Stalin, Mao, Pol Pot, etc....
The Christian religion in the USSR was allowed to survive under Stalin, and he in fact used it to his advantage during WWII.