There is not a folksinger worthy of the name who doesn't know lots of pro-war songs. They range from the racially motivated Arkansas 1st variation of The Battle Hymn of the Republic, to the blood thirsty "One Sunday Mornin', While On My Way To Mass", to the official "Star Spangled Banner" to the comical "Hitler Has Only Got One Ball" (to the tune of "Col. Bogey's March") and "'Round and around Hitler's Grave".
Most patriotic songs are connected to wars and were used to motivate the populace. In the American Civil War, Union troops marched to "Rally 'Round the Flag, Boys" and Confederate soldiers used "Bonny Blue Flag". George M. Cohan's "Over There" was as official a fighting anthem as ever was. I have done school assembly programs on the connection between war and songs. Believe me, for every anti-war song like "The Band Played Waltzing Matilda", there are hundreds like "The Battle of New Orleans".

                  Mike