First, well played. It seems atheists are just as ignorant about their non-faith as Christians are about their faith.
Second, you didn't pay attention. I'm not an atheist (well, I am by atheists definition but only as a consequence), I am an Agnostic.
Yes, I know an atheist is defined as one who has a lack of belief in any God.
But what is the test to be recognized as an atheist by others?
Just ask "Do you believe in a god or higher power?".
If the answer is not "yes", you got an atheist.
(Note the difference, not "yes" vs, "no".)
If an atheist behaves in such a manner that aligns with the morals Jesus' teaches even though they claim to be an atheist, shouldn't they be called a Christian?
Should they be called Buddhist, Shintoist, Pagan, Hindu if their behaviour aligns with those moral teachings? Atheism has no moral, so an atheist is free to be as moral as she wants.
According to Wikipedia, there are 500 million atheists in the world. How do we know whether someone who claims to be an atheist secretly believes there is likely a divine power, but claims to be an atheist strictly to avoid ridicule for believing as such?
If we were to weed out these fake atheists, would the 500 million number significantly change?
Here it comes, fake atheists. Well to distinguish "fake" atheists from Real Atheists
™, the answer to the question would have to be "no" and they would have to be able to make a conclusive argument for their atheism.