Blackface, which has an ugly history dating back to at least the fifteenth century according to historian John Strausbaugh, was used to portray demeaning and horrifying stereotypes of blacks. Such stereotypical imitation has not been limited to blacks, of course; actors tasked with playing stereotypical Jew Shylock often donned a fake nose and red wig, as did actors who were supposed to play Barabas in The Jew of Malta. Such stereotypical potrayals create a false sense of blacks, or Jews, or whomever becomes the target of such nastiness.
. . . His show is about pure hatred for conservatives in the same way that blackface was about pure hatred of blacks. In order to justify their racism, racists had to create a false perception of blacks; in the same way, Colbert and his audience can justify their racism only by creating a false perception of conservatives.
. . . The problem is this: will 50% of CBS audience simply go amnesiac on Colberts career-making hate?