The Nazis took over many traditional songs (including the "apprentice" songs, wandering songs, etc.) and used them for their own purposes, indentifying them with the Nazi philosophy, so after the war the younger generation wanted nothing to do with them. Recordings from this period are still around (even if only from German right-wing groups), and lyrics are on the Internet--many are grand songs in their own way, but I wouldn't be interested in singing or even hearing them--there are so many good German songs around...