Every time I hear the song, though, no matter who's singing it, nor which version, I get bothered.
I think it should go, "Oh, when will WE ever learn?" After all, it may be some "other" that does this -- the war-making and grave-filling -- but it's US that keeps it happening.
As long as it's someone else's damned problem, then we, the singers, can cluck our disapproving tongues. But when it's OUR problem, then maybe we'll try a little harder, eh?