These people are lost in their own worlds. They are the main and most important character and other people are simply NPCs to them. They haven’t learned to relate their own experience with the experience of others. They don’t consider there other genuine experiences outside of their own. Empathy is an abstract concept that means nothing but weakness to them.
They can learn to see the world and the people within it differently but it takes an inner awakening and personal effort that they are unlikely to muster the longer they exist as an isolated entity.
As much as I resent religion, I do believe it’s fundamentally a human problem. People everywhere have a tendency to corrupt beliefs in order to justify being assholes to one another.