My Culture is Better
When we look around at the various religions, without reading a word of their actual holy scriptures, we see disagreements worldwide, from the individual to the societal levels. Much of this is cultural "My culture came first and is better than yours" type of behavior. Often it is is nationalistic, but still coming from a similar mindset.
When these factors are taken into account, however, and removed from the equation, the "religious" differences are left. And these differences seem to become larger than life at times. Soccer and religion sometimes get people into very emotional states of oppositional consciousness. Soccer is more understandable, since it is a game of competition.
Does this mean that religion is also a game of competition against other religions? Good intentions are one thing, but the actual results become very important, certainly when big trouble breaks out. The answer to this question of why all the disagreements between the various religions lies in the way religions are mapped out mentally, and in the consciousness of the masses in the religions.
As with many of the really difficult issues of spirituality, the answers are usually found in the "usual" ways of finding answers. The disagreements are related to the attempts to "bend" reality in a certain direction. The direction of the way of each religion. So the answer is the same answer to why people tend fuss and fight in general. But the religious arguments become super-heated because of the emotional charge associated with religion, God, and so on. People generally have some intuition that the true reality of life is God and Soul.
But, because of "lifetimes" (soul projection body energy cycles) of desires and attachments to the physical realm, both material and sometimes rather spiritual desires, the chakra pathway to God and Soul is difficult to perceive. (even though it is there, ever brightly shining with its colors and its bright white light).
Antithetical Organized Chaos
And this being the case (of the long forgotten inner pathway, the inner Self, Soul, and the present Reality of God), the life force (prana) energy is turned outward into the senses, creating the world that we know. And he also says that we identify ourselves with a transient body and a world of antithetical (at opposition), organized chaos.1 So, the religions, being made up of “us” in this state ... the so called fallen state, are at odds much of the time. The organized (religion) antithetical (often at opposition with each other) chaos. Things often seem to be orderly, but our “left” brains are doing much of that with brain software. Not that God does not have a Grand Design for all Souls. We are not talking about that. We are talking about earth. No need to mix God's apples and earth's oranges.
Bibliography
1Yogananda, Paramahansa. God Talks With Arjuna. The Bhagavad Gita. Los Angeles: Self-Realization Fellowship Press, 1999. p.288.