[AmericaUnited]

That goes to population. There weren't 20 million expendable people in one geographic location under anyone's control at that time.

So how do you explain the other non-Atheist ideologies/countries during the 20th century, not murdering tens of millions of people as did the Atheist ones? Checkmate.

[steve-b]

So how do you explain the other non-Atheist ideologies/countries during the 20th century, not murdering tens of millions of people as did the Atheist ones?

As stated above, the reasons are 1)lack of political power (e.g. in western civilization, neither the church nor the state has enough control over the population to kill en masse, with the sole (as far as I recall) exception of the Belgian Congo) and 2)lack of opportunity (e.g. I'm sure the Iranian regime would love to kill millions of infidels in the name of religion if it could, but -- at least for now -- it can't).