"Since morality comes from God, Godly people should be the most moral."
You don't need fear of a sky daddy or a hell to be a moral person. I don't believe you do. I believe you need God to ground your morality but Atheists are very moral people on average. But if morals are decided by society and culture then they aren't objective, you can't really call anything another society or culture does wrong if they all support it within that system.
If God exists though there are some things that are actually wrong no matter what the public consensus is.
This is an interesting thought - that there's a certain baseline for human action that comes "through God". What makes it so interesting is that it has within it a very testable hypothesis, to wit: "Since morality comes from God, Godly people should be the most moral." This makes sense, doesn't it? After all, those most in tune with the Divine would be those who most fully expressed it in their lives.
There are several imperfect censuses (censi?) that place the prison population of the US as highly religious - that would seem to be enough to refute that hypothesis, but the studies are inherently flawed as prisoners will often say whatever will give them a perceived easier time of it in jail. There's a very valid question that simply asks: are prisoners who profess faith given preferential treatment? Sadly, that's often very true; social workers, judges, advocates, and even guards and wardens look upon a person's commitment to faith as a positive step toward rehabilitation, and often 'ease up' on prisoners who are especially devout. Given that phenomenon, it's not startling that most prisoners would claim to be faithful.
Godly people are the most moral but all believers are not Godly. Many believers don't follow the Bible Love your enemies, esteem others better than yourself etc. It doesn't stand to reason that just because a person professes faith in God they automatically become holy and perfect. The Bible talks of sanctification, putting behind sin and bad behaviour and practicing and learning Godly behaviour. The disciples didn't always do everything exactly right even after the Holy Spirit came and Jesus was resurrected.
Do Atheists really believe Christians have to be perfect for God to exist? The children of Israel were disobedient often as well.