From wikipedia :
«In the field of psychology, cognitive dissonance is the perception of contradictory information and the mental toll of it.»
Then someone who trust his ears someday suddenly discovered that he could not trust them anymore ... This sudden discovery is so stressful that he embark on his crusade because he is coherent and want to solve his own stress problem after this sudden discovery and adopt double blind test method with rapid switching to calm his doubts after every purchase and he begin to preach everyone about it as if each person was like him stressed by the discovery that our hearing is not always trustfull...😊
This is cognitive dissonance ...
Myself i slowly learned how to trust my ears in the limit of a specific domain of activity : acoustic of room/system and audio optimization ...For sure i can be deceived sometimes then i used simple blind test as a tool ...But i never encountered a traumatic experience of self deception as some high end costly consumers who became stressed by their experience and stressed by the sudden understanding about their self deception ...
Then i was never myself in a state of cognitive dissonance nor in a crusade for truth ... I stayed always relaxed and never stressed occupied by my acoustic journey ..😊
that is straight up cognitive dissonance