Mao and Stalin, both the heads of atheistic ideologies, killed far more than all the events you quoted combined. For the matter, the Nazi's were officially atheists, with documents showing they intended to deal with the Christian churches after the war.
Oh yes. I mean, after all, ISIS is atheist-inspired; the Crusades were atheist-inspired; and Christian America's hundreds of cowardly military invasions and occupations have been atheist-inspired. (Yes, the U.S. has carried out literally hundreds of military invasions and occupations - 236 to be precise. [see the Library of Congress].)
Too, some 80% of Scandinavians are atheists. Yet, Scandinavian countries sport that world's lowest crime and incarceration rates. In fact, Denmark, as but a single example, has closed nineteen prisons over the past ten years as its crime rates have plummeted and its ridding itself of religion has accelerated.
" Atheism is much more congenial to their line of work." How absurd.