It's not stupid loyalty and groupthink, it's instinct. During our evolution a person needed their groups acceptance to survive, and other groups were a potential threat. We've basically evolved to think of ourselves in groups. That's why we have patriotism, and why people will have rivalries with football teams, and why Texas wants to Texit... They are a group, and everyone else is a dangerous outsider.

Not saying it's good or bad, but let's accept it for what it is rather than insulting people for not being in the anarchist club. Because at that point you're no different.