Toadfrog, where did the German folk songs you've heard come from? I don't think the songs rediscovered during the folk revival by bands like Fiedel Michel, Liederjan, Moin and others - not to mention modern reworkings of these - ever made it to the States. The people who moved there in the 19th and early 20th century probably took with them the more polite songs that were widely sung at the time and forgot about the others, if indeed they ever knew them. I even have a CD of German emigrant songs. Have you ever come across any of those? Or artisans' songs? Wandering artisans could be a rather rowdy crew and had a whole song genre to themselves. Then there are those about monks and nuns, about highwaymen etc. Few of those were known to (or taken up by) the Wandervogel movement.