Race. It's that taboo thing that non-minorities aren't supposed to talk about. Weer'd has a go at it, and he is absolutely correct. It's a social construct.
That said, there are some in this country for whom race means everything. Racial identity is not just a part of who they are, it's central to who they are and therefore everything they look at is colored through a racial prism. As someone who really did take MLK's words to heart growing up, the divisiveness and hyperpolarization is disheartening. The more we make race an issue the more divisive it becomes, and that in turn creates a vicious cycle.
My grandpa is 100% hispanic. He came to this country because he wanted to kick some nazi ass and didn't think he'd be able to do that while serving in the Chilean navy. I have NEVER once heard him refer to himself as "hispanic," "latino" or any type of "hypenated American." He has, first and foremost, always been an American and proud of it. He raised his children that way too, and didn't speak spanish at home. Does that mean he disrespected his roots? No, it just means that race/ethnicity is not central to his identity. Was he discriminated against during his career because of the color of his skin? Sure, but I've never heard him blame racism. Ever. Not once have I heard him cry "poor me" or claim that some nebulous "white power structure" was allayed against him.
My Mom-Mom was German and Irish and fair skinned. My Grandpa was German as well, but would get very, very dark when out in the sun all summer. My dad get's dark enough in the summer that it wouldn't be all that surprising for someone to assume he's not white. My aunt syl (RIP) looked 100% hispanic. My mother and one of my younger sisters have hispanic features, and also get quite dark in the summer. My other sister and I? We have blue eyes, lighter hair, and are more pale.
We often joke that in family pictures we all look different enough that you wouldn't know we were family, but spend 10 minutes with us and it's abundantly clear we're all related.
Oh, and we all consider ourselves "White." The only time race becomes an issue for me is when my race becomes the issue. I've had plenty of flat out racial hostility directed at me because I'm "white" but that doesn't exist, and if it does I'm surely not supposed to talk about it.
For most of this country "race" really doesn't mean anything, yet for that we are "racists." That is the truth and I think that is emblematic of why race relations aren't better in this country.
Calling for calm, rationality, constitutional protections and objective analysis of the facts is in itself perceived and portrayed as "racist" and frankly, that's unbelievably depressing.
And frankly, Cerebral Palsy is as much a characteristic of an individual as race or ethnicity, yet you don't see massive, angry marches when some poor kid (or adult) is assaulted because of that or some other disability that they never chose to have, now do you? Then again, I suppose something like that couldn't be blown up for political and/or self-aggrandizing purposes, so it wouldn't do any good for the narrative of the left.