Betsy DeVos is not woke.    Bill Gates has not been to the mountaintop.    Nor is the Walton Family Foundation concerned with promoting civil rights.    So when white billionaires pour cash to charter school lobbying groups – as the Walton’s did Thursday for charter school protestors at an Elizabeth Warren rally – it isn’t exactly convincing.    Speaking at the historically black college Clark Atlanta University, Warren, who is seeking the Democratic nomination for President in…