So not all republicans are white supremests, but pretty much all white supremests are republicans.
But why? If you believe the way white people have done things in this world is the best out of any other race, you would have to believe the following ideas are great ideas:
1) Secure the border; keep non white people out.
2) Universal healthcare.
3) Free college
4) High taxes on the wealthy to fund social programs
5) Abortion is legal; and paid for by the government for all that want them up until 12 to 20 weeks into pregnancy.
6) Hate speech is banned
7) Transwomen are women
It sounds like claiming white culture is the best culture in the world is akin to saying social democratic policies are the best in the world (except for immigration).
Social democracy is western civilization.