People do not protect and defend their beliefs about their identities because they are logical or because the stories they have heard are correct. Rather, they grow up in environments that enforce these beliefs and identities upon them. This is their home, where they feel a sense of belonging.
It's the attachment that matters, not the logic, truth, or correctness; it's the attachment they have to these beliefs and identities and the group they represent. They feel compelled to be proud and to silence the part of their brain that seeks logical answers. Alternatively, they may bend the truth and create their own logic to ensure that these beliefs and stories are upheld.
If a discovery were made today that opposed their beliefs, a discovery so obvious that one might think it undeniable, people would still continue to believe in their existing narratives. They would find ways to mend the truth and the stories, reforging their attachments and identities.
Humans are not driven by logic, facts, or similar principles; it's all about feelings, how to keep oneself alive, and so on. A fundamental aspect like identity, and the belonging that this identity requires, means that if people challenge our collective identity, those around us might oppose us or even disown us. If we do that individually, we risk losing everyone, our safety net, and our security. This fear is what prevents people from questioning their beliefs or trying to understand the illogical parts of the stories they grew up with. Humans are fearful; we are such cowards that we cannot even admit our cowardice. Instead, we become defensive to protect what our “group” believes in.
People can usually think independently and avoid being overly insistent on their group identity beliefs if you engage with them on a one-on-one basis. However, in group settings, they often become less open-minded and tend to conform to the collective identity of the group...