Remember, this is the one-judge-in-the-world. I refuse to believe that there is any judge who could ever think that Seigenthaler was not a public figure - but given the number of my peers who have stated firmly that Brandt is only "border-line notable" or "non-notable", I have to assume it is possible a judge might agree with them, as they are equally rational and intelligent beings (perhaps with more legal knowledge than I).
Does it really matter about the judge? Does Wikipedia not have a right to trial by jury?
I don't think the legal definition of "public figure" and our definition of "notable" have much in common. If the information in our article is all published somewhere, then by definition he is sufficiently public for us to include that information in the article.