Because there are some religious people that are hypocrite.
Some of it is too little. I think that the majority of believers hypocrites. The only exception is religious fanatics, but they are even worse.Of course believers in the atheism religion are hypocrites. How can we tell? We can tell because nobody has any proof that God DOESN'T exist somewhere.
For example. Consider the topic in this forum entitled, "Astronomers have discovered 7 planets similar to earth," located at https://bitcointalk.org/index.php?topic=1801002.0. Have the atheists ever visited all of those planets? Of course not! So, how do they know that God doesn't exist on one of those planets? They don't know!
What is the thing that atheists DO KNOW? They know that they don't know if God exists on one of those planets or not. That's what they know. And since they don't know if God exists, why do they CLAIM He doesn't exist? It is because they are religious hypocrites, right? Their atheism religion contradicts what they know, which is, that they don't know about God.
Is God on another planet? Nobody knows. He might be on another planet. If He is on another planet, then He exists, right? Atheism is wrong because atheists don't know. This is only an example.
God might be right here on earth somewhere. Nobody knows about all the parts of the earth. God might be living in a part of the earth nobody has visited, yet. Atheism is wrong because atheists don't know.
What is the thing that atheists don't know? Atheists don't know that God does NOT exist. Atheism is a hypocritical religion.
So now you are already trying to prove or disprove that God does not exist?
As a religious freak, I'd concentrate on the proof that God does exist not that he doesn't. Unless of course you are already questioning your own beliefs. Congratulations, you might be closer to the truth than you think.
There is no God, never was. It is your mind playing tricks on you to help you survive.