How do you understand Confucius's sentence "Poetry can be inspired, observed, grouped, and complained about"?

The meaning of this sentence is: "Why don't students learn poetry? Poetry can stimulate emotions, observe society, make friends, and complain. You can serve your parents if you are near, and you can serve if you are far. King, you can also know the names of many birds, animals and plants."

Confucius (September 28, 551 BC - April 11, 479 BC), whose surname was Kong, and whose name was Qiu. , named Zhongni, was born in Zouyi of the Lu state (now Qufu City, Shandong Province), and his ancestral home was Liyi of the Song Dynasty (now Xiayi County, Henan Province). He was a great thinker, politician, and educator in ancient China, and the founder of Confucianism. Dacheng is the most holy teacher."

Aristocratic origin:

Confucius’s ancestors were nobles from Liyi (now Xiayi County, Henan Province) of the Song Dynasty, and their ancestors were Shang Tang, the founding monarch of the Shang Dynasty. After the rebellion of the Three Supervisors in the early Zhou Dynasty, in order to appease the nobles and descendants of the Shang Dynasty, Duke Zhou used the order of King Zhou Cheng to grant Wei Ziqi, the brother of King Zhou of Shang, to establish the Song Kingdom in Shangqiu and worship the Shang Dynasty. After the death of Wei Ziqi, his younger brother Wei Zhong came to the throne. Wei Zhong was the fourteenth generation ancestor of Confucius.

The sixth generation ancestor got the Kong family, and it was Kong Fujia. Kong Fujia was a senior official of the Song Dynasty and was once the Grand Sima. His fiefdom was located in Liyi of the Song Dynasty. He was later killed by Dazai Huadu during the civil strife in the palace. Confucius’ father and his son Mujin’s father, Mujin and his son prayed to their father, and prayed to their father and son Kongfangshu. Kongfangshu’s grandson Shulianghe was Confucius’s father. Shulianghe fled to Zouyi (now Shandong) in order to avoid the war in the Song Dynasty. He settled in Qufu City, Guangdong Province, and his official position was Zouyi doctor.