Why does Han Fei have to satirize Zheng people when he buys shoes to return pearls? Is there any historical relationship between them? Urgent, please answer as soon as possible. Thank you, please.

Han Fei was the son of Korea, a Korean aristocrat, and Zheng was destroyed by Korea. The three families were divided into Jin, Wei and Zhao each had their own glorious periods. Needless to say, Qin, Qi, Chu and Yan are all very strong, but South Korea is really lacking except for destroying Zheng at the beginning of its establishment (375 years ago). Therefore, the demise of Zheng has become an eternal and glorious memory of Koreans. After Han destroyed Zheng, he moved the capital to Zheng (now Zhengzhou, Henan). North Korean aristocrats face "Zheng people" every day. In order to recall their past glory, these Zheng people became the object of ridicule and teasing. This also shows that despite the Han Fei era (before 280? -Top 233? ), South Korea has taken Zheng as its capital for 100 years. Koreans and the original Zheng people have gone through three or four generations. It is speculated that the people of these two countries should not get along too much. However, judging from Han Fei's many jokes about Zheng people, the relationship between the two countries has not been settled, because the discrimination against Zheng people by Korean nobles has not changed much. So when he tells Zheng Ren's jokes, he makes readers feel that he is very happy. In fact, it didn't take long for North Koreans to face the same fate as Zheng people and become conquered people of Qin people.