I think as a shounen tagged manga, I can dig it for childish train of thoughts are shown. the manga editor must take pov of a shounen on the plot, just say typical weak ass growing into cool strong hero or discipline + effort equals good result, and that's what sold for Japanese kids audience. And here outside of japan, after translated and edited, the morale value just not fit well with some countries culture. And I also think, adults shouldn't critic what's childish childish, after all it's just a shounen manga.