Another note: I don't think rage comes from circumstances. I think rage comes from interpretation. Lots of people suffer. It's the narrative and the scapegoat that enrages folks, be they the Capitol protesters or anyone else. For better and worse.
I had a thought yesterday about suffering and class, and I think much of it boils down to this: If you're not fending off death, you're fending off depression. The former being the more material, but the latter can amount to living in an undead manner.
I'd say one way to elaborate your theory here is to speculate about how a conventionally rage-inducing set of circumstances can be spun, to be interpreted in different ways.
Within a capitalist culture, I'd say much of the rage is unnecessary and beyond circumstances, as you say, because of how one set of circumstances can be interpreted in relation to another set.
In this case, say my material circumstances are perfectly accommodating, materially, and that my suffering is more against depression than death. Odds are, if I attribute my suffering to my circumstances, its because my circumstances pale in comparison to even more accommodating circumstances.
And the interpretation of equivalent material circumstances can vary based on your ideological climate. What if you're in a more dharmically defined culture, perhaps one that conflates contentless with material ownership to less of a degree?