This is a great list. I’ve encountered that underestimating thing, too.
I’d add one more (could probably make a whole list of ten). If someone finds themselves being supercritical of black people they don’t know. For example, some type of discourse or scandal happens, and they feel a need to weigh in on it, with a scathing critique of what the Black person did wrong, or their character (unknown or just a celebrity, makes no difference), but they don’t have any of that same energy for white people they don’t know.
I see this a lot of this type of behavior in fandom, and with celebrities. There are a lot of people who don’t see themselves as racist, but when they see some discourse trending that involves a black actor, they will jump in to criticize and opinionate.