Religion also has trouble accepting a single unifying philosophy and is constrained by it's members willingness to deviate from the weight of it's traditions. How much easier would it be to achieve peace in Palestine if neither side was constrained by their belief that they were ordained to follow a destiny chosen by their god. When life is about living not about salvation the range of choices people make open dramatically. I'm not saying that this guarantees that all the ugly aspects of human nature vanish and our future is assured but that the ability to change ones position becomes more likely.
You are entirely right that any doctrine limits options, often in a negative way, and it can be very hard for there to be any fruitful dialogue between groups or individuals who each feel they are on the one true path. However I think some religions, including the RCC, are moving in the direction of being more accepting and more tolerant of different ideas.
The Palestine problem is a very good example. It is sometimes hard though to distinguish between racism and xenophobia which clearly exist independently of religion. There is no doubt however that bringing peace to that part of the world would be easier if Jerusalem were not so important to both sides of the conflict.
I kind of see it like a dynamic tension. Having some doctrines and cultural artifacts keeps communities together, helps enforce useful codes of conduct, encourages co-operation and charity etc, but if they become too restrictive or xenophobic they create a great deal of internal and external conflict, while if they become merely symbolic they lose their value as a cultural anchor or social glue. As with most things the trick is to find a functional and virtuous balance.