No, no, no! I don't think the history should be swept under the rug at all. What I think is that the history reflects well on present members of the Democratic Party. The political views of the Southern Democrats were unconscionably evil, and the corrupt bargain national Democratic Party figures struck with them was a terrible thing. But in a series of intense political battles, the Democratic Party eventually broke decisively with that heritage, prompting breakaway segregationist campaigns in 1948 and 1968 and eventually leading the bulk of the white supremacist constituency to drift to the Republican Party.
The significance of the history of race in America -- and of the centrality of the Democrats' corrupt bargain with white supremacy to American political history -- really shouldn't be minimized. But what it shows is that the Democratic Party's decision to embrace the civil rights movement and the Republican Party's decision to embrace opposition to civil rights has been integral to the Republican Party's political successes toward the end of the 20th century.