Republican vice presidential nominee J.D. Vance struggled over the weekend to defend denials by Mark Robinson, the Republican nominee for governor in North Carolina, after he made controversial comments on a pornographic website, which included calling himself a “Black Nazi” and defending slavery. A reporter for NBC Philadelphia asked Vance to react after Robinson denied making the comments. “Well, look, the allegations are pretty far out there, of course, but I know the allegations aren’t necessarily reality, and what I’d say is it’s ultimately up to Mark Robinson in North Carolina whether he…