Who do you think God is more mad at, lukewarm Christians or atheists? Is it possible that those who call on the name of Jesus, but also judge others is a root-cause of atheism? Revelation 3:14,15 tells me that the Lord is not happy with those who are lukewarm, and who are therefore judgmental.
I have found that the closer I get to Christ, the less I am able to judge anyone, I don't care if they are atheist, Muslim, or Jew. My judgement does not matter and God has proven that He is not fair. Fair has not one thing to do with it. If He were fair, we would all be damned. Praise God.
Can the bad behavior on the part of the Christian actually be the problem with the world?