The majority of black people (and the majority of white people) don't pay that close attention to politics. I think most people just assume that Democrats = good, Republicans = evil, wealthy racists. When I was in college it was taken for granted that Democrats were the party for the working class and the poor, Republicans represented evil corporations and war. Didn't really think about it beyond that. Of course as you get older your priorities change, kids, family, taxes, health insurance, etc. But your risk tolerance changes also, so some older black people might not want to take a chance on radical new policy changes which may or may not help them in the immediate future, so they stick to what is familiar. Most people will choose the familiar over the unpredictable.