So yes I would say people like Ruth Ginsburg who didn't believe in the 15th amendment allowing equal voting rights with regards to race, are racists.
This was an indigenous people treaty case, and when mothballed says "certain public elections" they mean "a single election for a position in Hawaii which was established in negotiations with indigenous Hawaiians in the 1970s. Not, however, a treaty obligation.
I don't know that I agree with RGB here, but I don't find that to be a racist opinion.