Our beliefs are largely conditioned by our upbringing, it is as if we are born to follow our parents/family and indeed most of us do. Political persuasion, for example, more often than not, runs in the family, once a Republican believer, seldom a Democrat convert. Some belief systems are capable of change others run a good deal deeper, particularly religions.
Belief systems dictate the thinking and practice of lifestyle, and to a large extent define our prejudices. What is true in one belief system is not necessarily so in another. The idea of the non-believer is the epitome of conflict. It is here that the intolerance of ignorance, the refusal to listen to another viewpoint is inevitably entrenched.
The good news is that virtually all belief systems including religions are centrally tolerant, it is only the extremist who sees the non-believer as a threat. Those that see the alternative belief system as simply that, are those who the world needs.
There is,, of course, the view that beliefs if they are worth anything, must be shared with those others outside the circle of belief. The record of missionary exploits is not good and history shows that the extremists seem always to get the upper hand. History is littered with examples wildly extreme acts of desecration of human life and values. All in the pursuit of spreading beliefs of one sort or another.
How then are we to fight against the extremes? The answer is to learn, to listen and to tolerate those other belief systems, not necessarily to accept them. To be aware that they have a place in our world despite the prejudices of our own history.