Hmmn, I have to tread very carefully here to avoid being heavily down downvoted. Please don't ask me to elaborate on 'why' in Germany past or present.

The Nazis did not celebrate Armistice Day. Instead the equivalent Nazi celebrations were the Heldengedenktag (Remembrance for the Heroes Day) which was (IIRC) the second sunday in Lent, this was a day of remembrance for all German soldiers and is closest to 11/11 as has ever been celebrated in Germany and the 9th of November - Gedenktag für die Gefallenen der Bewegung (Remembrance Day for the fallen of the movement) which celebrated the Nazi dead in the Beer Hall Putsch.

How did they celebrate? Well in the mid thirties, they would generally do something big the day before. And when I say big, I mean remilitarising the Rheinland (36), marching into Austria (38), that kind of big.

Post WW2 (1952) the Volkstrauertag was introduced, but its never really been celebrated AFAIK and most people couldn't tell you when it is (the middle Sunday in November, I think). The Day of German Unity is more important (3rd Octobr) is more important, but still only really observed as a free day off work, the real remembrance on this day is for people who died crossing from East to West.

We still have November 4th ("Victory Day") as a public holiday. The celebrations would have been started by the Corazzieri, who would lay a wreath in front of the Tomb of the Unknown Soldier (which is located at the Vittoriano), with the King and Mussolini standing nearby. A military parade would have then take place at via dei Fori Imperiali - hell, it was built for that very purpose! - and finally, there would be yet another speech; the King usually delivered his by radio, Mussolini liked to harangue the crowd from the balcony at piazza Venezia.

The tradition continues to this day: both the President and our Prime Minister go to the Altar of Fatherland and pay their respects to the Fallen with a wreath. But nowadays, all is very low-key (no parades due to budget concerns).