Ehh, this doesn't really change what he said. He's only saying the campaigns against them were racist, but still fails to explain how the people, who were affected and didn't vote for those candidates because they were non-white, aren't
It does in the sense that he's well aware that racism was used against them; he doesn't think he should call these racially-charged campaigns. They're racist campaigns. For the people, replace "aren't necessarily racist" to "don't feel they are" (which, again, doesn't actually mean they aren't) and that's the point. It's badly worded, but the main point he's making is that many white people do harbor racist views due to discomfort with black Americans, and the campaigns prey on that and affected the races on the margins. He's also saying that those who ran progressive campaigns in these redder states like Florida and Texas did a better job than the ones in Indiana and Tennessee because they excited progressives.