I think you have cause and effect reversed here. The original "pull" trigger was the automobile becoming affordable to the middle classes, making suburban living possible and leading to many leaving cities. The racist bit here is that many of these suburbs had covenants prohibiting non-whites.
The "push" factor came when poorer (non-white) people started moving into these vacated, now cheaper inner city properties. This in turn led more whites to leave, but here too the push wasn't just racism, but also concerns about falling property values, rising crime, etc.
Also, FWIW, as a non-American I found the SF of 2019 positively scary. Homeless camps in the Tenderloin, mentally ill people raving about murder on Market St, etc -- you don't see this kind of thing in equivalently wealthy European or Asian cities.