The outsider's view can be put down. Stereotypes place things in neat categories which we reference to predict events - how others may react etc. Categories have value in analysis but they may partial and not factual. Their use can lead to pre-mature, erroneous conclusions. Bounded rationality and tethered assumptions Group tend to suffer from their own bounded rationality.
Members reassure others that their interpretation and perspective on matters is correct.
Thjey come to believe what want to believe without challenging old assumptions. A marketing group wants its new product to succeed. The information must be wrong. We have everyone's best interests at heart. If we communicate and present our message propoerly people will come to understand.