This one feels like the key to me. I've spent a life around liberals, I'd describe them as earnest, disorganized, soft-hearted and prone to negotiating with themselves. But the conservative caricature is of uncompromising, steely-eyed fanatics executing complex plots to perfection. It's unrecognizable...
...as liberals. On the other hand, if you even casually watch Congress you know that Republicans are far more ruthless politicians. Their behavior with the previous president makes it clear that they don't really have principles beyond winning. They have think tanks everywhere coming up with new schemes to gerrymander, manipulate the media and who knows what else.
In other words, projection.
And I think you're exactly right here. They look at a situation and imagine how they would react, then ascribe that to the other side. They already seem scared of Black people, the idea of angry Black people with a justified grudge must cause a lot of cold sweats.
Of course, they could at least try to take the edge off that anger by treating oppressed people better now and building up some good will...but they don't seem to have that in them. It takes a lot of courage to let go and trust the process, these are folks who are afraid to live without a gun on them.