And these realities don't just exclude other religions. In America, people who believe the Bible to be completely accurate in every word have vastly different Basic Assumptions that the rest of society. They will interpret current events and find a way to fit them into biblical prophecy. And just as they test the world against their interpretations of truth based on their group's Basic Assumptions, they will even test their own people to make sure they are actual members, and not infiltrators wishing to dilute their beliefs. Anyone whose interpretations of current events are not the same as the group's will be labeled a heretic or an unbeliever.
Human conflict is a self-perpetuating problem.
We do not know for a fact that anything is true because we are humans, and our minds are interpretive machines. We may believe something with all our hearts and still be wrong. We might fight and die, or even kill, for our interpretation of truth, but it won't make it any more true. All we can do is learn as much as we can and then remove everything that cannot be true and start seeing what is left. It'll never be a perfect truth, but at least it won't be a self-created one based on our personal or our group's own Basic Assumptions.