I wouldn't necessarily read "has lost all credibility" as implying some longwinded thing about human rights in regards to the current case, that the credibility

I wouldn't necessarily read "has lost all credibility" as implying some longwinded thing about human rights in regards to the current case, that the credibility claims are "further than". There have been attacks and denunciations against the court and its credibility for quite a while. At the very least since that one nomination got deliberately stalled at the end of Obama's last term, but I hear there were people attacking the court even before then, when I wasn't paying much attention yet. Something about hanging chads in Florida for one. Or the previous before-my-time attempt at court packing.