Is it true that atheism has killed more people then organized religion?...

[Existentialist]

Re: the Crusades - I give little or no credibility to any pre-20th Century social or political history, I tend to think that within two to three generations we lose all the constructs to interpret past human behaviour accurately, we can only suppose things - and even then, only subject to the acceptance that our suppositions are entirely based on 20th/21st century constructs. Essentially, every generation must invent itself, and nothing of any use can be communicated to us from past generations whom we haven't met. I do suppose, however, that humans would have started killing animals before religion was invented and said it was alright. Most religious culinary edicts are based on what is healthiest for their population in time and place, probably based on trial and error, as the first people who ate pork in hot climates would have discovered to their cost.