The short answer is because it’s simply not true. This is not news to those of us who understand that such common and typical lies and deceptions and misrepresentations are promoted by liars for jesus who are determined to paint atheists as the cause for much suffering even when that is not historically true.
Steve Pinker offers us five fatal points to this absurd historical caricature in this pithy counterargument:
1. The premise that Nazism and Communism were “atheist” ideologies makes sense only within a religiocentric worldview that divides political systems into those that are based on Judaeo-Christian ideology and those that are not. In fact, 20th-century totalitarian movements were no more defined by a rejection of Judaeo-Christianity than they were defined by a rejection of astrology, alchemy, Confucianism, Scientology, or any of hundreds of other belief systems. They were based on the ideas of Hitler and Marx, not David Hume and Bertrand Russell, and the horrors they inflicted are no more a vindication of Judeao-Christianity than they are of astrology or alchemy or Scientology.
2. Nazism and Fascism were not atheistic in the first place. Hitler thought he was carrying out a divine plan. Nazism received extensive support from many German churches, and no opposition from the Vatican. Fascism happily coexisted with Catholicism in Spain, Italy, Portugal, and Croatia.
3. According to the most recent compendium of history’s worst atrocities, Matthew White’s Great Big Book of Horrible Things (Norton, 2011), religions have been responsible for 13 of the 100 worst mass killings in history, resulting in 47 million deaths. Communism has been responsible for 6 mass killings and 67 million deaths. If defenders of religion want to crow, “We were only responsible for 47 million murders—Communism was worse!”, they are welcome to do so, but it is not an impressive argument.
4. Many religious massacres took place in centuries in which the world’s population was far smaller. Crusaders, for example, killed 1 million people in world of 400 million, for a genocide rate that exceeds that of the Nazi Holocaust. The death toll from the Thirty Years War was proportionally double that of World War I and in the range of World War II in Europe.
5. When it comes to the history of violence, the significant distinction is not one between theistic and atheistic regimes. It’s the one between regimes that were based on demonizing, utopian ideologies (including Marxism, Nazism, and militant religions) and secular liberal democracies that are based on the ideal of human rights. I present data from the political scientist Rudolph Rummel showing that democracies are vastly less murderous than alternatives forms of government.
Enjoy the complete interview by Sam Harris with Steven Pinker.