Facebook isn't the problem. It's a function of its users. It is as much responsible for misinformation as a city park is responsible for the crazy guy shouting about the lizard people. The problem is all the users who actually believe anything they read via facebook.
Imagine one friend tells you "Can you please tell Adam X", but you know X is a flat out lie and is actually horrible and offensive. So do you agree to spread the lie? Oh and you're doing this free, and it's not your friend it's 2 strangers.