I think you are reading too much into his comment. You are taking it as saying X = Y when I think it was meant as X ⊂ Y, where X = "scared white, Christian, racist, xenophobic people" and Y = GOP voters.

We are in effect a two party system, at least for national offices and major state offices. Someone who falls under "scared white, Christian, racist, xenophobic people" has a choice: Democrat or Republican.

They probably dislike many things in the platform of both parties, but they almost certainly find far more they dislike in the Democrat platform than the Republican one. Hence, they tend to vote GOP if they vote.