I completely agree with you that many sides can be accused of ressentiment, and I had that in mind writing the article. Pretty much any negative human trait can be weaponized and the human tendency is to more readily see faults in others than in oneself.
All of human life, and perhaps especially politics, are strongly connected with self-identity. I wrote about that a great deal. Belief in conspiracy theories is fueled by identity issues. https://medium.com/inserting-philosophy/what-lurks-beneath-conspiracy-theories-57b7e0a0764a.
We do need a more positive outlet for political identity, but not sure what that is. Whether on the national or local political arenas, people’s ego-driven self-identities are running the show far more than desire for productive dialogue and actions.