Cognitive dissonance is technically when you already hold two strong opposite beliefs. For example, often teens hold the belief that they should wait to be intimate until marriage, based on Biblical teaching AND they believe they should be intimate to show “love.” I believe what you are describing is hardcore denial based on ego demanding they maintain their core beliefs, come what may. Cognitive dissonance happens once they embrace the truth but still believe the opposite strongly. As a therapist, I see this often, although, unfortunately, I cannot ethically insert my views. ❤️