Anyway, atheism overlayed on a society always ends in might-makes-right. Pre-1500, name the societies that were based on atheism. When did societies begin to diverge from "might makes right" justifications? You statement is based on far too few data points to contain long term validity.
None specifically. Many, however, were based on pagan humanism, which is the functional equivalent. Still, in 2,000 years of Christian culture, only 4.5 million people died violently in Christendom. That includes offensive and defensive wars. The Inquisition claimed only about 5,000 lives; the Salem Witch trials slightly over twenty.
Those numbers wouldn't even constitute a rounding error compared to what atheistic China, the Soviets, the neo-Pagan Nazis, and Pol Pot accomplished in the 20th Century.