Thank you, Roberto, for the information. Oh my, oh my - what a text. He doesn't know much about history, language, and songs.

Those "minnelieder" of the 12th and 13th century e.g. only survived because they were preserved in written form in monasteries (Carmina Burana) or by private collectors (Codex Manesse, now in Heidelberg).
The peasants did not rebel against the Teutonic Knights only, but against their barons and princes in general.
The lansquenets were not forced to fight anywhere. As I wrote above, they volunteered for the duration and got a contract. Part of it was where to go and whom to fight - and naturally the pay.

All in all a bit too romantic be be true. That's what I deplore with those agitating singers: no respect for the tradition of their elders, bending and massacring the songs to their political intentions, and telling lies about their origins. The worst is to take poems of well known authors of modern times and to tell the people they are protest songs of earlier centuries.
No, I can't stand such guys.