Of course the Republicans aren't going to attend a civil rights function. There's no upside for them to do so, even if they get a call from Colin Powell on the subject. They have other things to do, like raise funds for their next campaign, and reassure their base that the Constitution never envisioned laws like the Voting Rights and Civil Rights acts. Two full time jobs unto themselves. They've already addressed part of the Voting Rights Act in the Supreme Court.
Unbeknownst to them, they have already reached their high water mark. Look at their latest efforts to reach out to the last reservoir of untapped white voters (Jews), then look at Missouri