By focusing on shared experience of cultural context or upbringing, you're ignoring the shared experience of how people are treated by others. People do have things in common based on skin color. For example, my sister is Filipina. She lives in a white dominated area which has a lot of xenophobia about Mexican immigrants. She has experienced several events where she gets mistaken as Mexican, simply by her skin color and is threatened and/or told to go back to Mexico, sometimes quite angrily. These experiences are quite traumatic. The typical person doesn't make a close study of other cultures, so if they're actively racist/xenophobic/what-have-you, they don't look to the nuances of their target's background before they lash out. Being ANY minority, especially a visually identifiable minority, creates a shared experience regardless of peoples' actual backgrounds. This causes communities and identities to form as people group around shared experiences.
Yes, most ways of categorizing people and identities are arbitrary and diffuse, but in the end its people bonding over shared context and experiences, real or illusory, and I'd be hard pressed to call it silly, any more than other human behaviors that don't follow, I dunno, strict logic.
My only issue is the level at which that single one-word descriptor is used above all others. So much focus is placed on "black" "white" etc... that it devalues the nuance of other descriptors. Like "immigrant", "rich", "poor", "college-educated" etc.
Two people walk into a random corner store. One is a poor, immigrant person who happens to be white. The other is a rich, college-educated citizen who happens to be black.
Guess which one most shop owners are gonna be keeping an eye on.
I am a white father of black children. My hometown has a notorious speed trap that every person in the community knows snares black motorists. If my children were white, I wouldn't even have to mention it except in passing. But they aren't, and if they ever drive around in that town when they are older, I will have to specifically point out to them where the speed trap is to keep them safe from the people who are supposed to be there to protect them.
The one-word descriptor IS the most important one for dealing with strangers and law enforcement in the US whether anyone likes it or not. It's unfortunate and unfair, but unfairness and misfortune never stopped the world from turning.
The focus is there because race has been the descriptor of choice for generations to quickly, lazily and cruelly discriminate against minority groups, and the lasting effects haven't even been fully understood yet, let alone remedied to the point where we can just ignore what has and is still happening because of someone's skin color.
I believe fundamentally people are ill equipped to deal with this kind of complexity. When labeling people, rather than using a small set of discrete terms, it's closer to a probabilistic clustering problem where each individual is represented by a high dimensional vector where the clusters are generated on the fly and per-use, parameterized by time and space and the observer's viewpoint.
This complex representation is what the area of academia that studies identity has come to call intersectionality. I.e. being black and gay is a particular experience that is also modified by the person's other demographics.
But imagine translating that level of complexity to national discourse (i.e. a CNN article). Doing so leads to two simplifying approaches: one is to attempt to simplify by using broad categorizing terms ('black', 'white', etc); the other is to attempt to reject those terms by not using them. You're describing problems with the first approach. The problems with the second approach are that it can sweep actual experiences under the rug. For example, while 'black' is an incredibly broad term, that is in fact how a large portion of the population labels another large portion of the population, irrespective of their background, which does create a shared black experience that can and should be talked about, but then always at the risk of ignoring other labels that also make sense in context, such as wealth, education, etc.
I don't know a rhetorical way out of this situation. This is why academic texts (by that I mean authors who are attempting to tackle the subject without any undue attempts to simplify) dealing with the subject can become so twisted and hard to read, because actually describing the context of an individual person can lead to a per-person book-level explication of their experiences that also includes a not-insubstantial explication of the author's experiences.
This is a problem with language. Every time I'm personally in a situation that ends up getting written about in the media, a situation where I'm sufficiently involved to understand the nuances of what happened, the article feels like a comic book simplification and reflection of what happened. But then did I experience that event in the same way that other participants did? No. That's the subject matter tackled, for example, in Roshomon. An 'event' in history is a generalization and narrativization of something that will be probably be interpreted very differently by the actual participants involved.
The problem with exercises like what I just wrote is to use the lack of conclusive and easy categorization to justify inaction or disengagement, i.e. "There is no black identity, let's just treat everyone as though they're the same race." That flies in the face of a great deal of lived experience. Especially because a white person in America can afford to act that way, but a black person cannot.
Yes, most ways of categorizing people and identities are arbitrary and diffuse, but in the end its people bonding over shared context and experiences, real or illusory, and I'd be hard pressed to call it silly, any more than other human behaviors that don't follow, I dunno, strict logic.