You're calling all judges of the era racists? Racism was a policy, not a personality trait. Provide a single case where that happened. Lets see some evidence for your virtue signalling claims.
Yes this is silly. Pre-1994 judiciary had a large degree of independence and there were whites sentenced to death for the murder of black people.
No judiciary is ever 100% independent of the politics. But this is just the baseline.
We could spin that posters point and ask, when you have been oppressed by a race group before, can you as a judge be independent? So can a black person judge a white person when he may have in the past or his relatives may have been in the past on the receiving end of apartheid? This cuts both ways.
By the way, while I'm not comparing Nazi Germany to NP in any way, the Germans in WW2 also executed people who may have committed murder on their own too and against their enemies. I know of a case of a gentile killing a Jew who was in hiding and the Germans came and shot him on the spot. The gentile was a non German though in occupied conquered land though.