Richard Dawkins writes in A Devil’s Chaplain: Reflections on Hope, Lies, Science, and Love,

The human psyche has two great sicknesses: the urge to carry vendetta across generations, and the tendency to fasten group labels on people rather than see them as individuals. Abrahamic religion mixes explosively with (and gives strong sanction to) both. Only the willfully blind could fail to implicate the divisive force of religion in most, if not all, of the violent enmities in the world today. Without a doubt it is the prime aggravator of the Middle East. Those of us who have for years politely concealed our contempt for the dangerous collective delusion of religion need to stand up and speak out. Things are different now. All is changed, changed utterly.