Well, of course you CAN just sing harmony, but they changed the arrangement so that the old parts don't quite fit with the melody, at least on that song. I know you're not really arguing with me, but it's a curious kind of PC that would embrace the African National Congress, which openly espoused violence, and not allow The Battle Hymn. I think a lot of folk songs would do well. Ochs' "When I'm Gone" would be a lovely addition.