I agree that religion is often the excuse for war rather than the reason. But saying, "if either side had actually any idea of what true religion is ..." Is simply joining in with that attitude of " I know and you don't. " To dismiss war as "tribal" is to ignore all the politics and history of not only the region where the killing takes place but also of the world. From Pope Urban to ISIS reasons for "religious" war goes far deeper than who believes what. It's equally possible to dismiss (although I wouldn't) WW1 as a "family spat".