That’s fear responses. Bacteria in groups shy away from unfamiliar chemical transmitters too.
Finding subtle similarities helps. For example, two people complaining about “Big [somethings]” might be on opposite sides of a political fence for other reasons.
One complains about, Big Government and sees themselves as right-wing anarchist, the other complains about Big Corporation and sees themselves as left-wing anarchist.
Or, they each see themselves as “normal” and not anarchist.
But knowing that, there are ways to bring them together. One could point out how Corporations and Governments operate similarly and how neither one of us conversants have much say in what either does. Shared powerlessness in the face of differerng “bigs”.
So, by tackling specific issues, it’s possible to generate threads of connection.