My God - The majority of religions talk in terms of My God. My God is ownership of God. My God invariably becomes a collective Our God, truth, and dogma. Our God dogma makes us right and you wrong. Or, us being saved and you being damned. Harris proposed, "the central tenant of every religious tradition is that all others are mere repositories of error or, at least, dangerously incomplete. Intolerance is thus intrinsic to every creed." (2004) Dogma makes our religion having an exclusive knowledge of God, and that makes us superior. Religions have views of reality documented in their dogma. Religious dogma supports a theology of separation. Separation theology divides the superior from the inferior. For Eldredge, "cultural ideas seem deeply embedded in human life that other people are inferior." (2004) Wilson said, “religious exclusion and bigotry arise from tribalism, and the belief in the innate superiority and special status of the in-group.” (1998) I argue that the belief that others are inferior is especially pronounced for religion ---> our faith makes us special with our God. And, let me point out that My/Our God has led to holocaustic behaviors of annihilation, purification, and genocide to those who have the audacity to dare-to-differ from my/our truth. Question: “How much of this My God mentality has contributed to the instability of the world we live in?” #Balanceology.net
Those who control religion for their own power and profit are bound to make it divisive and tribal. Because they have nothing else to sell. If there was a god and that god was fair to everyone and everyone knew that god fair to everyone, then who would need religion? Unfairness is its only selling point.
Religious belief is inherently narcissistic, especially monotheistic forms.
In most cases it may not be the cause, it merely inflames negative behavior and thoughts to a dangerous level. The harder the indoctrination, the worse it gets because the purer you are, the dirtier everybody else is by comparison.
Your point that this particularly applies to monotheism is well-taken. It is inherent in monotheism because if there is "one true" god then by definition all other gods (and by extension all competing understandings of the same god) must definitionally be "wrong".
This is not nearly so true in polytheism. The way a cultural Hindu explained it to me is that every household chooses a household deity from the long list of Hindu deities, and gives particular veneration to same. If you visit someone else's home, you're expected to respect that household deity while visiting. There is no one right deity, it is a matter of choice.
Similarly in animism, there is thought to be a patron spirit of sorts for all sorts of objects and situations, a spirit of clouds, of weather, of lakes, of trees, etc. Perhaps even a spirit of a particular tree. As such, they are part of an organic whole, and not in some sort of competition.
It was only when humans decided that there had to be a single deity over all that rightness became elevated over goodness in a systematic fashion.