I think such a challenge would fail in any reasonable legal system. HN seems to be talking itself into a belief that these interviews have no relationship to actual programming work, but that's not the case and plenty of experienced engineers would step up to defend algorithmic questions if it ever moved beyond bellyaching in blog posts.

Of course the USA is ever more extreme and crazy when it comes to identity politics, so ago knows if the justice system is still reasonable in this regard. But I'd really enjoy watching people argue in front of a judge that working with tree structures is extremely irrelevant to programming.