I understand the protesters' point - this is not so much an academic course as a self-worth booster - but accepting it as a valid principle requires either accepting that blacks are simply inherently superior, able to understand and empathize with whites whereas whites are unable to do the same, or accepting that a teacher can only identify with and teach about people with the same skin color. Remember, the history of blacks and Hispanics in America is an intricate part of American history, not something that was experienced in a vacuum. (Which is rather fortunate as it would have been either unpleasantly loud or quite difficult to breathe.)
I can also support the protesters' point to a point, but there's an inherent flaw in that line of thinking. If you teach children that only people with the same skin tone (or at the least, only minorities) can teach them black and Hispanic history, then you've conditioned children to believe that their skin color (and/or minority status) defines them. And if you teach them that only blacks or minorities can do some things, they must either become racists or suspect that there must similarly be things that only whites can do. Neither of those are good things.