A religion is any cultural system of designated behaviors and practices, worldviews, texts, sanctified places, ethics or organizations, which relate humanity to the supernatural or transcendental. (Wikipedia). Religion is a belief in a system of how human communities should behave to be able to live and cooperate for the best of the tribe. It dictates the morals of the group as well as formulating rituals and customs. It has probably been a successful strategy in the past during evolution but it has been detrimental when tribes grew and interfered with other tribes, and today it is the cause of many conflicts and hostility.
Under this definition, ideologies such as Socialism, Communism, Capitalism and most other “isms” are also religions, although not related to the supernatural. Atheism, a lack of religion, does not fit in here since it is a rejection of religion and it certainly does not have a set of ideals or rituals to qualify for it. Atheists have no common set of rules or even ideology. They are all over the place. Secularism, when meaning the separation of Church and Government, guaranteeing the right to be free from religious doctrine in Law and Public Education is also not a religion although Secular Humanism could be considered one since it does outlines the behavior and practices in their various publications such as the Secular Humanist Declaration issued in 1980.
Having said that, I like to point out the ridiculousness of bringing up Hitler, Mao, and Stalin as examples that Atheism kills. Believing in god or not, or believing in an ideology or not, can indeed make you a killer but the motive is power and eliminating your opposition. One kills because of religion OR ideology; both are types of religion. Religion or ideologies kill to force their world-view upon others. Hitler killed because of Fascism, Mao because of Communism. Ben Laden killed because of Religion. They killed because of opposition to their belief system, including killing atheists.
That’s the difference. Religion, and certainly in many events in history, killed if one did not believe in the same religion. So stop the accusations that Atheism is a religion that kills. It is NOT a religion but rejection of religion. Atheist can still believe in ideologies such as Socialism. Fascism or Capitalism which they can hang onto fiercely and that is too bad because they are also belief systems and prevent reason and compromise to establish the secular laws and morals needed in today’s society.