And we can leave Hitler out of this, since you are apparently so thick that you don't understand the man's own words. Hitler called Christianity a "social scandal" against the German people and vowed the destruction of the Catholic church after he finished with the Jews.
We can also leave out the slaughter of the French Revolution, with infamous rape of the Vendee (nuns and priests being repeatedly raped to death, that sort of thing).
We can leave out the North Vietnamese communists because no one actually knows how many they killed.
When it comes to killing the innocent, nobody can beat the Atheists.