Well, it is actually about Bono encountering a soldier in Northern Ireland! I have read that in a few books including Eamonn Dunphy's Unforgettable Fire and Into The Heart, as far as I can remember. The fact is that British Soldiers consider themselves to be imposters in Northern Ireland, that they really shouldn't be there... So they are the "strangers In a Strange Land" as it were...
I do love the lyrics of this song, but It sounds just a little bit clumsy and awkward.
I have just listened to the song again there and I can see what you are getting at with your interpretation Bebe! It makes as much sense as mine when you actually listen to it!