Cognitive dissonance is the mental discomfort people experience when holding conflicting cognitions. It is a signal that our thinking doesn’t make sense and we need to change something to make that feeling go away. It is not hypocrisy or having contradictory thoughts. It’s a feeling we all experience. IMO exploring our cognitive dissonance is a useful way to better critical thinking. The people you are talking about are probably not experiencing cognitive dissonance as they have long since rationlised it away.