I think his point is that the ideology of the Democratic and Republican parties have changed drastically over the years. I'm a Democrat because I'm liberal, I'm not liberal because I'm a Democrat. If the Democratic party changed their platform and started embracing racist conservatives then I would no longer be a Democrat, but I would still be liberal. I know both you and
@blackangst1 understand this point.
Calling out a political parties platform 100 years ago (or even 50) is just silly and serves no purpose. Focus on the ideology, because that's what people care about.