In the years following the end of World War II, Argentina and other South American countries held considerable populations of German-speaking immigrants. Their interests were addressed by a magazine published in Buenos Aires titled El Sendero (Der Weg, or The Path/Way). This medium was able to carry messages protesting the conclusions imposed in occupied Germany as to historical fact. Holocaust revisionism was among these messages.
This is a pseudonym. The original Frederick Donauer was burned at the stake in Strassburg, Germany in 1348 by Ecclesiastical authorities. His crime: expressing disbelief in the Donation of Constantine, a Fifth-Century forgery claiming that the Roman Emperor Constantine had conveyed (his) sovereignty over the Western Roman Empire to the pope and the pope's successors through all time. The Roman Catholic Church acknowledged that the document was counterfeit as early as two centuries after Donauer's death, and has ever since, so we know that Donauer was martyred for disputing a then-officially protected lie.
Because many today are persecuted, jailed, deprived of their careers and livelihoods for expressing their disbelief of lies about the Holocaust, Dr. Arthur Butz in his monumental The Hoax of the Twentieth Century examined the "career" of the Donation of Constantine and compared it at length with today's doctrine of the Holocaust.
Today's Frederick Donauer uses this name as a necessary precaution to avoid being martyred for protesting a lie, as so many have been and continue to be.