Why did Song Gaozong kill Yue Fei?

First of all, it was very unwise for Yue Fei to talk about "going straight to Huanglong to meet the two saints". The "two saints" are Song Gaozong's father Song Huizong and Song Gaozong's half-brother Song Qinzong, who are the Emperor Tai Shang and the last emperor of the Northern Song Dynasty. At that time, Zhao Gou finally had a chance to become emperor. If Yue Fei really succeeds in the Northern Expedition and successfully rescues the "Two Saints", the status of Emperor Zhao Gou will be restricted and threatened. Second, Gao Zhen's works. In that era when there were signs of war, military commanders held a high position. With the constant fierce fighting of Yue Fei's army, in ten years, the army led by Yue Fei recovered a large area of lost land north of Huaihe River. The civilians in these places will not recognize the Southern Song Dynasty imperial court that abandoned them and fled alone. They will only recognize Yue Fei's Yuegujun, and Song Gaozong is bound to worry at this time. Yue Fei's achievements: Yue Fei was an outstanding commander in chief in the Southern Song Dynasty. He attached great importance to the people's resistance to gold, and created the plan of "connecting the river with the new moon", advocating that the people in the north of the Yellow River and Song Jun should cooperate with each other to recover lost land; Manage the army, reward and punishment are clear, discipline is strict, and you can sympathize with your subordinates and set an example. The "Yue Jiajun" led by him is known as "freezing to death without demolishing the house and starving to death without being captured". The Jin army has a comment that "it is easy to shake the mountain, but difficult to shake the Yue family army" to show its sincere admiration for the Yue family army. Yue Fei's literary talent is equally outstanding, and his masterpiece "Red Anger over the River" is a patriotic masterpiece that has been passed down through the ages, and later generations have compiled a collection of works.