I also read this book about the "Diary of a Madman" by Lu Xun for my religois and ideolofy projects in high school, its quite the shocker to once again see the last line "save the children", the story focuses about an old friend's younger(?) brother, who is yes a madman, he sees his society and even his brother as cannibals, but all this was because of his increasing insanity, it made the hate about how hypocrisy reigns in a place that believes in Confucianism. So yeah, its all about a madman's perspective how the ideology of Confucianism is not seen at all in his society, leaving him to a belief that the people that can live normally on that society is cannibals who does not care to other people and lives for their own gain or "nutrients", that's why he also said that saving the children, because maybe their are SOME children who is not tainted by the hypocrisy.