It wasn't about trading one black for another. The issues in this race really mattered for a change.
How'd you miss that after reading it? Or did you read it thoroughly?
Take a look again - he's talking about traditional black politicians (i.e., liberal, Democratic black politicans). And this DOES spell a change in the black electorate - there are more conservative blacks emerging and asserting themselves overall.
And that fact does hurt the traditional black political power structure - badly.