Barry Goldwater and Milton Friedman (at least if I remember correctly the relevant passages in Capitalism and Freedom) were against Federal intervention to protect African-Americans from segregation, even segregation imposed by state and local governments.
I don't know enough about Barry Goldwater's views. But I'm pretty sure that Arnold does not remember correctly Milton Friedman's views. His post caused me to review Chapter VII (titled "Capitalism and Discrimination") of Milton's Capitalism and Freedom. I can't find any reference to Milton's views on federal intervention to protect African-Americans from segregation. But I did find Milton's clearcut statement of principle against local and state governments' imposition of segregation.
FEPC [Committee on Fair Employment Practices] legislation involves the acceptance of a principle that proponents would find abhorrent in almost every other application. If it is appropriate for the state to say that individuals may not discriminate in employment because of color or race or religion, then it is equally appropriate for the state, provided a majority can be found to vote that way, to say that individuals must discriminate in employment on the basis of color, or race or religion. The Hitler Nuremberg laws and the laws in the Southern states imposing special disabilities upon Negroes are both examples of laws similar in principle to FEPC.
In researching the FEPC, I find that it began due to an executive order by FDR in 1941 and was focused on discrimination against black people by defense contractors. I doubt that Milton would have opposed that order: after all, it involved government spending and he always favored neutrality in government spending: that is, not having government discriminate, or support discrimination, against a particular group. But I think that by FEPC legislation, he had in mind some broader proposed legislation, which, apparently was never passed, to ban discrimination by employers generally. That certainly is consistent with how the above passage reads.
But back to the point. Given that Milton did oppose FEPC legislation and likened it, in principle, to Hitler's Nuremberg laws and the laws in Southern states that required discrimination, we can be confident that he opposed both the Nuremberg laws and the laws in Southern states. Of course, we cannot be confident that he favored federal intervention to overturn those laws. He simply does not address that issue. Perhaps Arnold has some other article by Milton in mind?