And who can deny that Stalin and Mao, not to mention Pol Pot...

And who can deny that Stalin and Mao, not to mention Pol Pot and a host of others, all committed atrocities in the name of a Communist ideology that was explicitly atheistic? Who can dispute that they did their bloody deeds by claiming to be establishing a "new man" and a religion-free utopia? These were mass murders performed with atheism as a central part of their ideological inspiration, they were not mass murders done by people who simply happened to be atheist.