1. Many people believe that their view of existential threats is universal. They can't believe that the other group may reasonably see other things as existential threats.
2. Party, this skepticism is justified. To make things more complicated, the social/media bubbles do influence people and can make them perceive certain things as threats, while they are actually not so important to them. Of course, nobody admits that their own views could have been heavily influenced by their own social/media bubble. But the other side is, of course, uneducated bigots, or brainwashed clowns, or something similar.
3. I've seen people from both sides who would project values of their tribe when they have no skin in the game, but once they do, their stance reverses to the opposite. A girl I used to know is a staunch leftist and always talks pro-immigration. However, when she had to rent out her apartment, she rejected all candidates who looked/sounded like an immigrant.
The issue is that their activities are motivated by a fundamentally different version of reality. Which is a serious practical concern for all groups.
Because I believe that actually no common group has a very accurate version. They are just flawed in different ways.
Thats a interesting way to think, would you like to expound that from both sides perspective?