What do you mean by pointing fingers at mulberry trees? The origin of idioms and the explanation of detailed words

The phonetic notation is ㄓˇㄙㄤㄇㄚㄏㄨㄞˊ Chinese pinyin zhǐ sāng mà huái, from Jin Ping Mei Hua Ci: "Every day refers to mulberry cursing, all kinds of praise." Interpretation means that mulberry trees scold locust trees. A metaphor for scolding this person on the surface is actually scolding that person. Also known as "referring to mulberry and cursing." Also known as "pointing at mulberry and cursing". Metaphor clearly refers to this and secretly scolds that. There are so many butlers in our family, which one is easy to entangle? If you make a mistake, they will joke, and if you make a mistake, they will complain. (Qing? Cao Xueqin's Sixteenth Story of A Dream of Red Mansions and the Fifth and Ninth Stories of A Dream of Red Mansions: "Don't criticize others." The 69th time in A Dream of Red Mansions: "All the girls and daughters-in-law made a few remarks, referring to mulberry's lovesickness and secretly sneering. Chapter 22 of Rain Flower in the Sky: "He and I have never had a good look all the year round, but we are just being sarcastic and pointing fingers at mulberry trees. Mao Dun's "People in a Small Circle": "Before class, I listened to Mrs. Bei's cynicism and boasted. "Similar words refer to scolding the West, referring to the cock scolding the dog, holding a gun and a stick, pointing to the bald donkey scolding the monk, pointing to the mulberry and saying the opposite, calling a spade a spade, cutting to the chase and beating drums.