it really isn't as simple as you make it to be
Sure it is. History closed the book on Nazi and fascists years ago. There is no reason to quibble about a few definitions. The answer to the big question is clear for all to see in Buchenwald, Auschwitz, Dachau and the other camps. There is no moral equivocation big enough to blur the definition and the true intent of the Nazis.
As far as von Brunn is concerned he supported and followed neo-nazi groups, he wrote about the threat of "liberalism" and followed the nativist veiw of the Consitution that he claimed was subverted by the Jews. It doesnt get much clearer than that.
DHS sez
(U) Rightwing extremism in the United States can be broadly divided into those groups, movements, andadherents that are primarily hate-oriented (based on hatred of particular religious, racial or ethnic groups),and those that are mainly antigovernment, rejecting federal authority in favor of state or local authority, orrejecting government authority entirely. It may include groups and individuals that are dedicated to asingle issue, such as opposition to abortion or immigration.
Case closed