You could claim that Black otherness has special characteristics and this being hackernews I would assume good faith and believe you that racism in its non-outward facet is palpable and ethically bad. But that's not what you said -- you said people compartmentalize and that's bad period. That's an interesting kind of misguided.
Dr. Martin Luther King Jr is spot-on in his frustration with "the white moderate, who is more devoted to "order" than to justice; who prefers a negative peace which is the absence of tension to a positive peace which is the presence of justice; who constantly says: "I agree with you in the goal you seek, but I cannot agree with your methods of direct action"; who paternalistically believes he can set the timetable for another man's freedom; who lives by a mythical concept of time and who constantly advises the Negro to wait for a "more convenient season." Shallow understanding from people of good will is more frustrating than absolute misunderstanding from people of ill will. Lukewarm acceptance is much more bewildering than outright rejection."
And its not just racism, its sexism, classism, homophobia, xenophobia, transphobia, child soldiers in Africa, terrorism abroad, FGM, corruption, homelessness, child abuse, cartel violence, drug epidemics... Seriously impossible to grasp. And moreover, the vast majority of people do not publicly observe offenses at the same rate as people who receive offenses so most of the time its just concerns that one reads off the internet or hears second hand. All this stress and empathy over things that don't even exist in your sights... I know many people will think this is a gross argument, that I am saying to remain ignorant or inactive while people are being oppressed, but at some point you have to just throw your hands up, resolve to do the right thing when you encounter a problem and live your own life.
This problem is something that ted kaczynski wrote about in detail and I think its an even more important problem now with information spreading so quickly, so much call to activism, and even dramatization of issues.
I think the underlying assumption is that a "racist" is someone who spouts bigotry 24/7, and that racism is black and white (pardon the pun) rather than a spectrum, where even an otherwise "decent" person can act or say something racist on occasion. This is why the common refrain after a person does a thing that is blatantly racist is "I am not racist - everyone who knows me knows this is not who I am" despite the empirical evidence.
It was a smart and funny talk, and I'm now looking forward to reading her book: https://www.amazon.com/dp/B07638ZFN1
People can grasp hate, and violence. But they can't really see the effects of simply seeing someone as "other" based on race. And it's everywhere in the US.
It's strange. Americans just don't have deep vocabulary for ethnicity, really. It's all just race.