Why did the last sentence of Lu Xun's Diary of a Madman say "Save the children"? What is the explanation of this sentence?

This sentence is the central sentence of the full text, which shows the author's inner helplessness and heartfelt sadness. Reading this article highlights the cruelty and badness of social reality in China at that time. From the children in this article, the author sees that these children are not cold-blooded and heartless, but only influenced by the harsh environment, so this sentence is the inner pain of his calligraphy, and it is also calling for the hearts of China people who are still sleeping.