The liberal side of the Internet has amused itself all day with Conservative Teen, a magazine that looks likely to repeat all the success of Tea Party Review. The Glee takedown is getting the attention, but is the real huh-maker article.
Click through and you find that Reagan's argument has two parts.
1) Black unemployment fell during the Reagan years.
2) In his personal interactions, Reagan was colorblind.
That's basically it. But black unemployment fell during other presidencies. Other presidents managed to avoid being racists. (Not you, Woodrow Wilson.) The "really, though, black voters should naturally vote Republican" genre is large, and once you get past Thomas Sowell it's not too rigorous.