I've spent a few hours today reading your posts about Bickford's analysis, and enjoying myself immensely. Thanks for thinking hard. If you're feeling put-upon, remember that she isn't blaming architects for the state of the world, so you don't have to be defensive. She is asking you if there's anything you can do to change things, though...
The other thing is that you can't really cast this as a chicken-and-egg argument -- does design make us segregated, or does our desire for segregation make us design certain ways? The answer she poses is "yes to both." The question is whether we want to change it, and then whether we can, and then how we can.
Let's take Detroit as a case study. The past century of Detroit can be summed up in two sets of interwoven tensions: cars and industrialization; capital and labor. Detroit was a French and English town with a fortunate spot on the Great Lakes; it was easy to get things in and out by ship, and it grew. Then... Henry Ford and the assembly line. All of a sudden, nearly every car in the world was being made there, and they needed workers, and lots of eastern Europeans were arriving, and so Detroit became a German-Polish city. The English left for Grosse Pointe to escape the dirty Polacks, but they still owned most of the major businesses, and came in by train.
During and shortly after World War II, Detroit made even more cars, along with lots of defense-related stuff like planes and tanks, and they needed even more workers. Blacks moved northward, and Detroit became a German-Polish-Black city. About this time, two things happened: cars were relatively cheap due to industrial success, and Eisenhower decided he wanted America to have its own Autobahn, which he'd seen during the war. So we got the Interstate system, which bypassed cities in order to keep vehicle speeds up to 70 mph. Well, that let the Germans and the Polish leave town, too, because they could drive 25 miles to work but not have to live there. And Detroit became Black.
So we've got two pieces of Modernity working at cross purposes: industrialization bringing a workforce together, and individual cars letting the workforce fracture into distant ethnic enclaves. Detroit becomes poorer and poorer (it's now half the population it was in 1950), and can barely afford government services. The police are still German and Polish, though, since the civil service jobs got passed down through political patronage. So you've got a poor Black city policed by Whites who live elsewhere, and you get the riots of 1967-71. (Note that the common term is "the Detroit riots," but the term in the Black community is "the Detroit uprising" or "the Detroit rebellion." Language matters.)
Through the '70s, the automakers and the United Auto Workers held each other more or less at a standstill. But then we started to get Toyotas and Datsuns (remember Datsun?), and unionized labor was seen as unaffordable. Michigan lost a huge portion of its manufacturing to the South, where unions weren't well established and people would work for less. (I have a strong memory from my own Michigan childhood of a factory a year closing.) And Detroit became poorer still, with unemployment over 20% during the early 80s.
To follow this through the 90s and up to the present day, not only is unionized labor unaffordable, American labor is unaffordable. So all the factories that moved from Michigan to Alabama are now moving from Alabama to Indonesia. But I can get a television at Walmart for $179.99, so it's all good.
No evil mastermind made all of this happen, conspiracy theorists aside. We could have made it stop, though, and never did. Lots and lots of seemingly benign individual decisions -- about privacy, about "good schools for our kids," about affordable cars and TVs -- have added up to social disaster for millions. And that, I think, is Bickford's point.