Sometimes people hold a core belief that is very strong. When they are presented with evidence that works against that belief, the new evidence cannot be accepted. It would create a feeling that is extremely uncomfortable, called cognitive dissonance. And because it is so important to protect the core belief, they will rationalize, ignore and even deny anything that doesn't fit in with the core belief.
Frantz FanonMy intimate knowledge of many central African tribes has everywhere convinced me of the necessity that the Negro does not respect treaties but only brute force.โโข General Adrian Dietrich Lothar von Trotha on German South West Africa โAt the level of individuals, violence is a cleansing force. It frees the native from his inferiority complex and from his despair and inaction, it makes him fearless and restores his self-respect.
Frantz Fanon