Why is there more Bi-racial African American involved in Politics than pure darker blacks?

We actually don't know what the various percentages are. A lot of people are involved in politics that aren't the elected officials, so we never see them except locally. Also, even among 'Africans' there are light and dark blacks..not to mention the fact that a fair number of 'whites' have a black relative or two. What you have here is a question without an answer. Anyway, why do you ask?