"Atheism is a central pillar of the communist worldview, and as such communist governments have always persecuted theistic religions, usually with tremendous brutality. As in, "Off to Siberia with you"."
That is bullshit, 'off to siberia with you' was for any political opponent, it didn't discriminate between the religious or the communist reformer, or anyone else.
And there is nothing inherently atheistic about an economic system which requires sharing, infact Christianity could be viewed from this point of view. And never mind the Kibbutz, ("Kibbutzim began as utopian communities, a combination of socialism and Zionism" - wikipedia) The fact is communist ideas are compatible with religion.
The example of a russian system which was essentially russian in character (authoritarian, centralised, vicious, just like all russian systems of governance before or since, for at least 300 years) the Soviet Union was more Russian than it was anything else, and Russians had been religious and not, while still killing people.
*cough* bullshit *cough*
Once more, people can kill for Communism, for Islam, for Christianty, for revenge based on clan, territory, or nationality - but atheists are a non-identity, some atheists form their own group, the philosophical humanists. And I doubt they have committed many murderous outrages, but since they are a group i'm sure people could kill to protect their humanism.
Still, not FOR atheism...