>>512718373 (OP)
During childhood development they are crammed like sardines in with the absolute worst examples of human beings on the planet. It's only natural for them to recognize that they're a literal cancer on the planet. So, they construct a narcissistic defense mechanism that helps them cope with the intolerable hell that is objective reality. They're basically living in an AR world and any attempt to pull them out will only sink them deeper into the delusion.
Most people do this, but basically the more crushing that objective reality is the stronger the delusion needs to be.