Religion is the oldest con game and the scourge of humanity. Postulating the existence of God, he and/or she is the same energy or being for all of us.
Christians and Muslims, Sunnis and Shiites, Catholics and Protestants have been blaming and vilifying each other for all of modern history and herstory. Fanatics and fundamentalists thrive on self-righteousness, hatred, anger, intolerance, and above all, the thirst for revenge.
They wade in each other's blood. They are blessed with laser vision for the faults of their enemies, but a bottomless capacity for denial along with the utter inability to perceive the mote in their own eyes.
And an eye for an eye leaves the whole world blind.