By its insistence on total unity behind one God and one religious doctrine, monotheism often leads to oppression and tyranny. In his book, The Psychology of the Religious Life (Chapter 25, “Standards of Religion”), George Malcolm Stratton writes:
“For the monotheist is apt to overprize the mere unity in his Ideal, forgetful that unity, if it grow too great, is tyrannous. Moral dignity, unswerving sympathy, and justice are, after all, more important elements in the divine conception; and we may better believe in these great qualities, though vested in many gods, than adopt a monotheism that leaves them out. Indeed, more than once in history a divine unity and concord has been attained at a cost of human colour and the rich play of interest and feeling… The Ideal is not merely a unity; it is quite as much a wealth and a diversity.”
A monotheistic region can be particularly useful for uniting a tribal society under one tyrant and forging a united army that will wage wars for plunder and conquest.