Whether you are atheist or not, you have to agree that atheism is simply another belief system/religion that requires "faith". First, you cannot prove there is no God, so the assumption/belief that there is no God is a belief that requires "faith".
Now, let's not get into the fact that this "faith" atheists have are different than the faith of true Christians. Because the faith atheists have does NOT require proof. While the faith of Christians rests on the fact and prove that God is real and loving and kind and forgiving, and righteous, and holy and all the attributes and characters of God and what He had done for us. So Christian faiths relies on something real and solid, historically and personally (experimentally).
So indeed, the "faith" atheists rely on is actually an irrational or self proving belief that requires no objective validation. In fact, if you are rational and honest, you cannot be an atheist, because you cannot rule out the possibility that there is a God until you have proven beyond all reasonable doubt that there is no God. And I can say that for the past 6000 years of human history, the overwhelming majority of ALL human beings believed and experienced the reality of God or some other supernatural beings. So you have to be pretty hardcore to ignore and dismiss all those "evidences" or the "possibility of the existence of a god" to believe that you have proven the non-existence of God.
Now if you truly believe there is no God and the world is materialistic, then you should live your life to the full extend according to your belief and world view. The materialistic world view is Marxist and Communistic and Fascist in general. Those schools of thoughts all were based on the believe that this world is purely materialistic. In a materialistic world, a human being is amoral. Because there is no higher authority, God to judge what is moral and what is not moral. So the government became the final authority of morality and in fact, whoever is in power usurps the place of God. This is why totalitarian states exists. Because there is no God, no higher authority, no higher Judge, the government becomes the final voice in everything and since the government is made up of sinful fallen humans, you know what will happen, disasters and catastrophes.
As you all know, the largest lost of human lives came at the hands of atheistic governments: Soviet Russia, Nazi Germany, Communist China, Pol Pot, etc. So I think it is a pretty good prove that a pure materialist worldview doesn't lead to anything resembling a liberty and free society.