Part of it seems to be based on rhetoric.
Progressives in the Sanders mold tend to frame racial issues as part of, and downstream from, broader economic issues.
Establishment Dems are much more likely to acknowledge racism as a real issue in and of itself, which might be pandering but that works.
Andrew Parker
what's interesting about this split within urban Democratic Parties is that faction aligned with the professional gentrifier class supports more generous policies for the poor and minorities and the faction aligned with actually poor and minority voters is more likely to oppose them.
mtsw
It’s interesting how some version of this map replicates itself in every city election in America.
Traditional redlined burbs: the conservative candidate
Professional class renter neighborhoods: the progressive reformer
Traditional Black/ Hispanic neighborhoods: the establishment Dem