One is forced, even willing to accept other opinions, even if they are based on lies. Tolerance grows with experience until an incident occurs, where tolerance (strengthens by education) does not apply anymore. No tolerance is absolute. For everyone there is a tolerance-limit. Each challenge will upset seriously. Even as a rigid command of morality, the demand of tolerance is not useful. One who would be prepared to tolerate everything would not be able to see any value in anything.