I think the author has probably mistaken an effect for a cause. And (unhelpfully) conflated "race" with "socioeconomic level." It wasn't whites who fled Detroit, it was the middle class--who happened to be disproportionately white. But middle class people of every ethnicity fled.
This is my last post in this thread because I'm sure Porky will close it down. I disagree with your assessment that discounts the significance of race in favor of class. Race and racial politics, as suggested by the Keith Richburg (a Detroit native) article I posted earlier in this thread, appears to have been a significant contributing factor to Detroit's downward spiral during the last half of the 20th Century. It is certainly true that the middle class appears to have abandoned Detroit, but it started with white flight perhaps influenced by the race riots of 1967, school busing, public housing -- all during a time of extreme racial strife and polarity in our Country.
Politicians, engaged in racial politics, also shoulder a lot of the blame too, so I'm not at all suggesting the toxicity that caused rampant crime, poor schools, substandard housing, inferior municipal services, and a culture of despair was all caused by white flight, but it began with that exodus and once a tipping point occurred that was absolutely nothing done to reverse it.
It's true that the Black middle class (and that perhaps of every other ethnic group) also abandoned Detroit but this was much later during the decline. Saying that this was simply a class exodus does not take fully account of the racial elements that triggered this decline. We're not color blind now and certainly weren't in the 1960's and 1970's when the decline went into full tilt.