I am a native of Japan, where my mother grew up in a Russian Orthodox family. About 1% of Japanese are Christians. Unlike Korea, where the trauma of Japanese conquest and then of the Korean War has led to rapid growth of Christian and quasi-Christian (e.g. Unification Church, AKA "Moonies") churches, Japan has a dedicated secularity that has concentrated more on identity as Japanese rather than as Buddhist or Shintoist (native animism akin to Native American religions).

The Japanese Army conducted incredibly brutal violence on people in Korea, China and the Philippines, without religion ever entering into it. Nationalism and a belief in the superiority of the Japanese race, without any specific belief in the afterlife, motivated massacres and kamikaze attacks. No heaven was necessary. Not even an international utopian vision like Communism was needed. Just Japanese people thinking of themselves as the best of all possible nations. Just overweaning pride, hubris without gods.

Looking back, this motive for conquest seems to have been the one that animated Menelaus at Troy, the Greeks and Macedonians under Alexander, the Romans, the Mongols, and the various Germanic tribes that are ancestors of modern Europe. It motivated the Aztecs and the Maya and the Inca.

Neither Christianity, Islam nor Judaism is needed to created conquest and brutality. To the contrary, until those religions began to make inroads on how people behaved, no one thought that the world could or should be different. Are in fact the people who are most obedient to religious belief actually a threat, or is it people who might use a veneer of religion to sanctify their own ambition and tribalism, as the Ku Klux Klan did? Their use of a burning cross was both a mockery of Christianity and an adoption of the same use of the cross as was made by the Romans: to threaten and intimidate. What passage in the Sermon on the Mount tells men to wear masks and murder people of other races? What verse in Paul's epistles invites Christians to give vent to their lusts for power, wealth and sexual conquest?

It is in fact the opposite. It asks Christians to reject the ordinary behavior of the world around them, and become holy, set apart, a slave of God rather than of their lusts and ambition. The short letter to Philemon asks him to lay aside the legal status of his slave, Onesimus, and instead accept him as a brother in the worship of Christ. It exhorts Philemon to love and tolerance, instead of the violence which Roman law said was his right as a master. Jesus spoke about the hypocrisy of those who claim to be more righteous than others, but who disobey God's laws enjoining justice and love, highlighted by the parable of the Good Samaritan. The source of intolerance and violence is in men, without any help. It is their natural state. If we are lucky, they allow religious belief to change their nature.