My father was an occupation troop in Japan right after WWII ended. He used to tell is various stories about that, and the joke was always that he enlisted at 17 when he looked like he was about 12, and he always thought the Japanese must have been looking at him and thinking to themselves, "How could we have lost a war to those guys?" At any rate, the point is that whether by family lore or in textbooks, Americans learn history as it pertains to America, as is to be expected. We learn more about earth that about Mars because we live here, not there. In Indiana we teach our students a unit on the history of Indiana, but not any units on the particular history of Arkansas. We live here, not there. Indiana is "centered" in at least that aspect of our history classes just as, presumably, Arkansas is centered in grade schools in Arkansas. And America is centered in all of them, at least until you get to later in high school or college.
Suppose I moved my family to Japan, and my children learned the history of WWII in Japanese schools. Many topics would probably be taught differently in a telling that centered on the experience of Japan. So be it. I might disagree with what they emphasized or what facts they thought important enough to include or meaningless enough to exclude from the text. It would be the same war, but a different story.
If we had conquered Japan and annexed it such that it was today one of the states, a star on our flag, the telling of WWII would be a huge bone of contention, as it is regarding Mexico in many places in the Southwest. America's story would not just be multi-faceted, but the facets would be contradictory and mutually-exclusive. Everything would depend on whose telling was "centered."
Wilkerson argues that upper caste people like me assume that our telling is central. If you center the experience of what we now refer to as white people, slavery is a sad, shameful aspect of the story of America. It is important, but not central. But if you center the experience of African-Americans, the story of America is simply about slavery and subsequent oppression. Slavery is not a facet of the story, it is what the story is about. The 1619 Project seeks to center the experience of slaves, but goes further than that in claiming that this story, the one in which the center of the story and the purpose and essence of the American experience is racial oppression, is the "real" story of America.
Here is the rub. Japan has a story. Germany has a story. Russia has a story. America has two (or more) contradictory stories. Multi-culturalism demands that no story be centered. But a story with no center is a story with no shape. Anything with a shape or an outline has central things and peripheral things. By dissolving artificial race/color identity groups, we can have one story that features slaves and slave-owners, rebels and liberators, and incorporate multiple points of view without contradiction. But if we codify race/color identities, such that people with dark skin today must identify with slaves and people with light skin must identify with slave-owners because the artificial caste-by-color-system must be preserved, we'll always have two clashing stories and eventually become two separate nations altogether.
On page 43 of my library edition, Wilkerson writes, "Slavery is commonly dismissed as a 'sad, dark chapter' in the country's history." She then goes on, "...but the country cannot become until it confronts what was not a chapter in its history, but the basis of its economic and social order. For a quarter of a millenium, slavery was the country." [emphasis in original]
Simply put, no it wasn't. Slavery was the country only if you center that experience. Slavery was there but only a facet of the story, and a fairly incidental facet at that, if you center the Puritans or, say, the Saxon migrants who came here for religious freedom prior to the Civil War. Notably, Wilkerson says the country becomes "whole" by decentering the white experience and then centering the experience of people oppressed by whites. THat doesn't work. The country becomes whole through an honest telling of history from all sides in a way that does not perpetuate false group identities.
Toward the beginning of Caste (p.19) Wilkerson writes, "Thus we are all born into a silent war-game, centuries old, enlisted in teams not of our own choosing. The side to which we are assigned in the American system of categorizing people is proclaimed by the team uniforms that each caste wears, signalling our presumed worth and potential." I think that an apt metaphor in many ways. For me, the obvious thing to do is to stop wearing the uniforms, or (since we can't change our skin color) stop acknowledging them or categorizing individuals by them. For Wilkerson, the answer seem to be make the losing team the winning team by decentering the team that has hitherto been centered. In other words, the problem isn't the assigning of teams by uniform but with which team wins.