Judge them by their fruits.

Poignant observation. There's a certain genre of righteous outrage that has pervaded the internet for over a decade now. It's a performative sort of anger. The targets are too vague to be assailable in any meaningful sense - the real goal of it is to get people worked into a frenzy so that they connect around that mimetic rage you mention, and also so that they pay attention to the author's writing.

I think that, like you mentioned, you can identify that type of anger (and the people who peddle it) by its fruits. Does it leave people with a clear path of action to do something meaningful and creative (or at least creatively destructive) afterwards? Or does it leave them worked up into a rage with no outlet except more typing in the comments section?

Here's a thought, though - your warning about mimesis is also one that is being repeated in different forms by a great many people. It seems the new subculture is one that would promote things like hope, reconciliation, and honesty over collective outrage.

It's not exactly new. Or different.

But maybe that's the point. Maybe we need different values to guide our actions than simply rebelling against the norm. I'm pretty sure that a commitment to a higher ideal like truth, or to the betterment of others, is more likely to send someone down the path of uniqueness. And even if it doesn't it will at least put you in the middle of a good crowd.