I think if you're looking for a song about the pointlessness of killing, perhaps that would be "And There Were Roses." But "White Orange and Green" is clearly a song of Irish patriotism and hence Irish Republicanism. The English soldier decides to harass this girl who is flying the Tricolour (which would have been quite illegal in older days) and she responds that if he wants the flag then he must fight her for it. "there's no use in fighting a girl of sixteen, who would die for a banner white, orange, and green" is not meant to say that fighting is pointless but rather that the British holding onto their rule in Ireland is pointless, because there will always be even the most unlikely of rebels (a girl of 16) who will be willing to die for their country. That has always been my interpretation, but i would love to hear the "missing" verse.