My reasoning was that if your political party/orientation includes racism, then this would make this a political reason

If your political beliefs include racism, you are a racist who uses politics as a weapon. This is post hoc rationalizing to give an excuse for racist beliefs and using the political machine to harm people.

There isn’t much difference in my mind between people who support racist parties and people like David Duke, the only difference is Duke is willing to be open and honest about his beliefs. And while the party has shunned Duke himself, good luck finding major differences these days.