Read any history of 30 years war- start with the Encyclopedia Britannica, and go from there - they would have a bibliography. And as has been noticed to you on this thread before, in religion wars the fight was - expressly - for the sake of, and in the name of, a religion [whatever religion]. Human sacrifice was again done in the name of a religion. Causation there is self-evident and self-proclaimed. The wars and crimes of atheist dictators were never done for the sake of, or in the name of, atheism, but rather for much more mundane purposes [personal aggrandizement, power struggle, territorial conquests, racial theories, class struggle, enemies of the people, collectivizations, great leap forward, or rather sideways, and so on]. thus you would have a hell of the time trying to establish causation with atheism.
"Human sarifice"??? In the European wars?
Did you get this stuff in some crazy history course from some weirdo, or do you like making things up to post and positing them again so you can re-read your brilliance?
Get a grip, perhaps even move to Cuba where you can be religion free. Or go back to the workers paradise of the Soviet Union where surely you won't be exposed to superstition or other horrors of religion........
The wars of religion were also waged for "mixed motives." Bohemond took the cross during the First Crusade because the Normans wanted to displace
the Greeks as the dominant power in the East. The Thirty Years War began because the Hapsburg emperor wished to gain control over all of the Holy Roman Empire. The French supported the Swedes rather than Austria because they wished to prevent the Emperor from doing this and surrounding France on three sides. Don't forget that the leader of France was a Cardinal of the Church of Rome, but put politics before his faith, in part because he knew that the Emperor was not engaged in a crusade against the protestants but in
an effort to make the Empire (Germany) the most powerful state in Europe.
Where the Church has used the sword it is because she has forgotten the three temptions of the devil, one of which is worldly power. Christ could not be "turned" but rhe Church often has. Communists, however, subscribe to
a worldy utopia. Not God but blind necessity commands them to do what they do. The atheist does not believe in God but he believes in Demiurge.