This was something that bothered me too. I love Luffy's personality, but after the war it seems a bit tacky that he's still the way he is. You'd expect him to mature at least a little bit after that kind of traumatizing experience. The kid had the guy die in his arms (I still think it was stupid how it all happened). Again, I adore Luffy's personality, but from a storyteller's perspective I have to admit that I see little growth from Luffy as a character. To me, it basically seems like that entire issue really didn't matter end(except making Luffy more of a dramatic character/give him an excuse to have that stupid scar on his chest). Same for Sabo's death too for that matter, though I expect he's still alive and will be Ace 1.5 in the future. Anyway sorry about all that, I think I got into a bit of a rant myself.