People can be heartless, unless they are vegetation. What does this mean?

No one can be ruthless without vegetation, that is to say, people are not flowers and trees, but full of feelings. This sentence shows an attitude of loving life. As a thoughtful and emotional life, people should have the mentality of loving and cherishing life. This sentence comes from the seventeenth time in the Water Margin written by Shi Naian in the Ming Dynasty: Everyone says: From above, the villain doesn't need vegetation. The Water Margin is a heroic legend and one of the representative works of China's ancient novels. It is based on the story of Sung River Uprising. Sung River Uprising took place in Huizong period of Northern Song Dynasty, and it is recorded in History of Song Dynasty, Biography of Huizong, Biography of Hou Meng and Biography of Zhang Shuye. Since the Southern Song Dynasty, the story of Sung River Uprising has been circulated among the people. Zuiwengtan Record records some independent legends about heroes of the Water Margin, while The Legacy of the Song Dynasty combines many stories of the Water Margin, which is very close to the novel.