Why do cultural conflicts occur?

Culture is not just a matter of clothing, food preferences, and rituals relating to religion. It is essentially a matter of values. While most people living together will tend to behave in a broadly similar manner, the differences not being of any great significance, they can be divided by faith. This occurred when religious institutions devised dogma to separate the sects within a religion, or more significantly to keep apart the diverse religions purporting to pray to the one and only God. Why should this be so? Institutional or personal ego? Or the possession of esoteric knowledge somehow not available to others?

What happens after death? In my case, I am comforted that a friend, a born-again Christian, promised, just before her demise, to keep a seat for me (the metaphysical Hindu).

In the realm of other knowledge, especially scientific knowledge, it used to be held over a few centuries in recent times that all change, whether geological, environmental, zoological, etc. is gradual – like a pacific sea eroding the coast or beach incrementally. However, catastrophic cosmic impacts are known to have obliterated fauna and flora in pre-history. They may have caused major genetic changes in the survivors, which eventually may have resulted in new fully-formed divergent animals. This is denied. That is to say that this could not have happened because there is no proof available. Does that denial not involve a cultural position, a value?

In the 1950s on, cosmic catastrophes, and the arrival of new forms of infectious bacteria from space, seem to have been accepted by many; while the steady-state incremental-change theorists preferred what seem to me to be semantics to explain away exceptions to their position. One of these explanations is the concept of punctuated equilibrium, backed by impressive speculation of how fully-formed new species could have suddenly occurred. The reality?

If there is so much metaphorical blood spilt by both religionists and some scientists, could one expect any agreement in the realms of human behaviour and the values underpinning them?