Phizzy: That is so sad Ron.W, minds not just closed, but welded shut. That is a condition that is unlikely to change as long as they live.
It sounds that way, but I have to wonder. I think they say that to get people to stop talking about it. If they can convince you that they cannot be reasoned with, then perhaps you will stop and they will not have to deal with questions or arguments that they fear might 'stumble' them.
For as long as I was PIMI, I was convinced that I had the truth. Anything that might seem like a reasonable counter-argument had to be some form of deception, a bad argument intentionally dressed up to fool me. Once I was outside of that bubble, I realized that I simply hadn't wanted to hear anything that could chip away at my beliefs. The human desire for certainty makes it easy for us to fool ourselves.
But we can still have that epiphany --that moment of clarity-- that shakes our worldview and forces us to reevaluate what we believe in. It won't happen for everyone, but I think that even the most stubborn person can go through an experience that frees them from their self-imposed mental prison.