Why do many believers insist on repeatedly pointing to the crimes of 20th century dictators who led officially atheistic societies as some sort of evidence of their god's existence? It makes no sense. If the rivers of blood on Stalin's hands and Mao's hands, for example, are supposed to prove there is a god, then what do the oceans of blood on the hands of several thousand years' worth of religious kings, queens, presidents, popes, priests, generals, Crusadersm jihadists and tribal chiefs prove? It's not, of course, but if bodycount is somehow the measure of a god's likelihood of existence, then believers lose. It is clear that humans are quite capable of killing with or without images of gods bouncing around in their heads. If anything, however, history suggests that the concept of gods makes the idea of massacring your fellow man (and women and children, too, of course) a lot easier to act upon.