There's a bit of racial cheating going on here by assuming the reasons that black/hispanic people are leaving cities are identical to the reasons wealthy whites are leaving cities, and that the trend started at the same time, follows the same lines, or ends up in the same suburbs. It's all glossed over by calling suburbs diverse by citing demographic percentages of all people who live in any suburb.
Black/Hispanic people have generally been priced out of cities by gentrification, and have been forced to move to places that are even farther from jobs and services than the previously neglected urban areas that they came from, and this started when millennials moved into the cities from the suburbs. Black people in particular have had a Southern migration because Northern black people are often only two or three generations from the South anyway, so they have family who can help with shared housing, childcare, and leads on employment.
This could be easily shown by showing rates of outmigration by group over time. Chicago's black population was dropping while its white population was rising. It would also be shown by individual attention to the suburbs that are being moved to, not only would you find that they were very segregated, but you might notice that plenty of them are hellish and poverty-ridden compared to the cities that people moved from.
I might as well quote the entire discussion of ethnicity, which occupied the body of a paragraph with nearly unrelated first, second, and final sentences. Maybe the word "urbanizing suburbs" in the context of an increase in amenities worked as a subconscious trigger to discuss black people moving to suburbs.
"The allure of suburbs has been a trend more than a half-century in the making, but covid-19 offered an additional boost. “Urbanising suburbs”, as Mr Clark them, are gaining amenities but keeping their characteristic sprawl. Contrary to the stereotype of identical white homes with white occupants, today’s suburbs are ethnically diverse. Wendell Cox of Demographia, a consultancy, estimates that 86% of the population of major metro areas live in the suburbs or exurbs. That includes 90% of whites, 83% of Latinos, 81% of Asians and 76% of African-Americans. Latinos, in particular, have been relocating to suburbs at greater rates in the past two decades: since 2000 their number has risen more than 50%, compared with a 20% rise for African-Americans and Asians and just 1.3% for whites. Ross Perot, Jr., a real-estate developer, says he’s “never seen as many people moving into Dallas. It’s shocking.” But far more people are going to the suburbs surrounding the city."
Note: a 20 year trend for non-whites, and a statistically insignificant blip for whites. Yet the article paints everyone as young upper middle class urban professionals trying to dodge taxes and city government.