Really, is that why you get christian communists?
http://en.wikipedia.org/wiki/Christian_communism
I mean Marxist communism, not utopian, Christian, et cetera, which were not the intellectual background of the USSR, China, Cambodia, Vietnam, Cuba, et cetera.
Atheism isn't a philosophy, a religion or any other category you wish to put it in. It is merely the non-belief in a god or gods. I get tired of this old canard being trotted out time and time again.
That's nonsense. Atheism is a philosophical position. It is the disbelief in God, which is itself a question of philosophical import. There are also many philosophies which can be described as Atheistic amongst which would be Marxism, Epicureanism, Nihilism, the philosophy of Schopenhauer, Nietzsche's philosophy, et cetera.
No one is claiming Atheism is a religion, though. It has no churches, no rituals, no expression of the numinous, or anything else of the sort.
Those millions were not killed in the name of atheism. Communists had a tendency to kill anyone who did not agree with their way. Intellectuals were normally the first to go, and guess what, you find that most of these intellectuals were atheists. In the killing fields of Cambodia just wearing glasses was enough to get you murdered as it was thought intellectuals wore glasses.
I will also point out that during WW2 Stalin, an atheist and a communist opened churches and encouraged attendance in a way to bring the Russian people together.
Those killed were killed under the understanding of these regimes' Marxist doctrine. Marxist doctrine is officially Atheistic. Marx does not quibble on this point.
For a good scholarly source on Stalin's massive persecutions of Christians and others, please see:
Dimitry V. Pospielovsky. A History of Soviet Atheism in Theory and Practice, and the Believer, vol 2: Soviet Anti-Religious Campaigns and Persecutions, St Martin's Press, New York (1988) p. 89
Stalin removed some supression in order to rally the Russian peasants behind the Soviet war effort. Your claim that he helped the church, however, is equivalent to saying an arsonist who builds you a hut is helping you after burning down your mansion.