I might agree that there are some interesting dynamics here and that they relate to this set of values, it's just that "X is being treated as white" is not necessarily a good way of describing them. Using that kind of wording is just assuming the conclusion - and while "white" and "non-white" may have been used in that way by some, it's only a small part of how these terms were used and it's hardly what most people think about as "white" today.
"What fuels structural, systemic racism" is another can of worms entirely and I see little reason to get into it here, other than to note that our aforementioned attitudes to class, wealth, gratification etc. might just as well be "fueling" other systemic social problems that people don't generally describe as "systemic racism", such as the opioid overuse epidemic among lower-class whites. So again, bringing race into the description of these problems risks adding confusion for little gain.
I think you're starting with the implied assumption that "white" is some objective thing that exists outside of the cultural convention that establishes it. But that's exactly my point - it doesn't. Marco Rubio is white because society treats him as white. I am white for the same reason. The actual color of our skin is not primary here - it's the social convention that makes it relevant.
And yeah, this is the historical meaning of "white". Consider the one-drop rule, both as a legal concept, and as a social convention. You could be white as snow, and yet the moment the society knew you had a black ancestor several generations back, you were treated as black - and thus, you were black. In other societies, it was different - e.g. the Spanish system of meticulously tracking blood percentages, and a formal hierarchy based on that, made it possible to "whiten" a bloodline.
The one-drop rule is no longer a broadly accepted social convention by itself, true. But while it had been, it created numerous derivative cultural markers, above and beyond skin color, which continue to be the basis of the social conventions establishing race today - distinctive names, for example, or use of AAVE. Somebody can still be white as snow, have stereotypically European facial features and hair etc - but if their name is DeShawn or Shanice, and they "talk black", they will be categorized as "black who can pass as white", and treated as such. Scenarios where their appearance isn't in the picture at all - e.g. that famous study with swapping names on resumes - make that rather apparent.
BTW, the opioid abuse epidemic is very much a manifestation of systemic racism - the reason why it started in poor white communities is because they are more likely to get an opioid prescription to begin with, and because the prescriptions are more generous (and thus more ripe for abuse). These both stem from long-standing racial stereotypes - one about blacks having inherently higher pain tolerance [1], and another about them being less responsible and less able to exercise self-control. Ironically, as those stereotypes are getting addressed, the epidemic is starting to affect black communities more.
But you're absolutely right that not every social problem is about racism, even when it stems from some social value that is also used to define race. For example, the overemphasis on "rugged individualism" destroys informal community safety nets regardless of race, and the adverse effect is the same for somebody in the same position on the economic ladder. It's brought up more often specifically in the context of black communities mostly because theirs haven't been destroyed as fully as those in white communities. So the process is much more apparent there to begin with - and then economic effects of systemic racism (i.e. the fact that black communities are much poorer on average) make the negative effects of this destruction much more blatant.
> I think you're starting with the implied assumption that "white" is some objective thing that exists outside of the cultural convention that establishes it.
It's not "objective" or outside of culture - on the contrary, it is definitely subjective and inter-subjective. It's what some people have been expected to identify as for quite some time, "as a social convention". I don't think the current "social convention" agrees with e.g. "Marco Rubio is white because society treats him as white". Not because of the color of anyone's skin, or anything like that - but because he is widely identified as Latino/Hispanic, and a widespread "social convention" treats that as something other than white. (Perhaps this sort of identity is less socially important than it formerly was, but that's quite different from positing a sort of "honorary white" identity wrt. Rubio or anyone else.)
> ...For example, the overemphasis on "rugged individualism" destroys informal community safety nets
Is it really the overemphasis on rugged individualism that does this? Some people might dispute that, and blame widespread dislike for traditional values or traditional community institutions - something that, for better or for worse, seems to be very much part of the "progressive" ethic.
"What fuels structural, systemic racism" is another can of worms entirely and I see little reason to get into it here, other than to note that our aforementioned attitudes to class, wealth, gratification etc. might just as well be "fueling" other systemic social problems that people don't generally describe as "systemic racism", such as the opioid overuse epidemic among lower-class whites. So again, bringing race into the description of these problems risks adding confusion for little gain.