The reason I didn't respond to the "It sounds Buddhist" comment is b/c I think it's pointless to try to speculate as to the "meaning" of this song, especially this early on. Fair enough to say I'm not sure I agree with your analysis...or that the sentiment as intended in the song is Buddhist (though I agree in general it can be interpreted the latter way). There is no "right" answer, and if the song is any good then in can be interpreted in many ways. Though my suspicion is that U2 intends it to be about the world's poor.
In any event, at the moment, the "There is no them, there is only us" is attached very much to the "charity" song, and Africa AID, all all the other sentiments U2 has been associated with along those lines...and for now I'll take it at face value that that's the way they intend it here.
BTW, despite the "father" reference in this song, I largely thought of it as Bono speaking in the third person. It's hard to imagine Bono is singing about himself here. If he's singing about his own father, I guess I'd be a little disappointed that he's returning to that thematic ground yet again. And I'm not quite sure I'm willing to concede that every time Bono yells out "Father" he's talking about Bob Hewson. I'd like to think he has more lyrical range than that.