Personal discontent drives outrage against others?

I treat this with some skepticism but intriguing none-the-less. From Moral Outrage Is Self-Serving, Say Psychologists by Elizabeth Nolan Brown and from the original research, A cleansing fire: Moral outrage alleviates guilt and buffers threats to one’s moral identity and Zachary K. Rothschild and Lucas A. Keefer.

From Brown's summary:

Ultimately, the results of Rothschild and Keefer's five studies were "consistent with recent research showing that outgroup-directed moral outrage can be elicited in response to perceived threats to the ingroup's moral status," write the authors. The findings also suggest that "outrage driven by moral identity concerns serves to compensate for the threat of personal or collective immorality" and the cognitive dissonance that it might elicit, and expose a "link between guilt and self-serving expressions of outrage that reflect a kind of 'moral hypocrisy,' or at least a non-moral form of anger with a moral facade."

The stridency of one's outrage against others is a function of one's own sense of personal immorality.