Christmas I dont think many soldiers thought that way back then on the german lines, if any and that mindset is too cold and modern.
After all remember the tale of what happened during one of the christmas's of WW1 and I remember reading in Günther Rall's autobiography (RIP OCT 09 age 91) they used to make sure the american pilots got out and SURVIVED once they shot them down.
not many if any people were looking for bloodshed towards the end of the war in the german populace, the new german hello/goodbye was switched by most people from heil hitler to überleben Sie (survive!) they also tried to kill hitler themselves and were planning to surrender germany peacefully in 44 if it had worked.
It wasn't like they were dealing with the japanese where that would have been an appropriate mindset to deal with there samurai like training on Iwo Jima and no surrender mentality which 2 nukes finally solved, hell when you come right down to it he seems like a WW2 version of Agent 47 there.
also thats supposed to help him deal with his fear and his guilt conscience of not helping his unit and killing someone who probably has a family waiting at home as well? that is probably one of the worst things you could tell someone like that and it could possibly lead up to a private pyle kind of situation with the wrong guy.