> These data show that only about one in eight white students (12.9%) attends a school where a majority of students are black, Hispanic, Asian, or American Indian. (We refer to this group collectively as students of color hereafter.) In contrast, nearly seven in 10 black children (69.2%) attend such schools (see Figure A).

That seems less like segregation and more of just statistics. If black students are a minority, then by definition they won't be a majority in a random subsample.

> As shown in Figure B, black students are also in economically segregated schools. Less than one in three white students (31.3%) attend a high-poverty school, compared with more than seven in 10 black students (72.4%).

That's probably the stronger argument in your link. That outcome isn't surprising given that most school funds come via property taxes - if most economically depressed areas are minority occupied due to lower costs, then those same schools would also be economically depressed.