What is the reason why Emperor Wu of the Han Dynasty gave himself an "imperial edict against himself"?

In his later years, Emperor Wu of the Han Dynasty wrote himself a letter of "the crime of wheeling a platform", mainly because he recalled his life and was militaristic, which caused great losses to the Han Dynasty, so he wrote a letter of guilt.

Emperor Wu of the Han Dynasty can be said to be an emperor with different opinions in history. During his reign, Xiongnu, Korea, Baiyue and other places were pacified, and the territory of the Han Dynasty doubled, making the Han Dynasty a great power in the world. For any emperor, expanding territory is a great achievement. However, it is precisely because of years of war that Emperor Wu of the Han Dynasty lost all the treasury left by Emperor Wenjing. In order to raise military expenses, he did not hesitate to increase the taxes of the people, which led to the displacement of the people and made their lives difficult. Sima Guang once commented on Emperor Wu of the Han Dynasty in Zi Tong Zhi Jian, and there was no fault of the emperor. In other words, Emperor Wu of the Han Dynasty not only did not lead to the demise of the Han Dynasty, but also made the same mistake as Qin Shihuang.

Emperor Wu of the Han Dynasty was militaristic all his life and made great achievements, but in his later years he could not help but be crony and pursue immortality. The emperors of feudal society, regardless of historical evaluation, will be superstitious about warlocks when they are old and want to live forever. Emperor Wu of Han Dynasty is no exception. He was bewitched by outsiders, forcing Wei Ruyun and the prince to die. He was even more crony in selecting officials, attaching importance to jesters and close relatives, and turning a blind eye to the chaos. It can be said that his achievements in life were destroyed in his later years.

Li Guangli, the eldest brother of Emperor Wu's harem, has no ability to lead troops to fight, much worse than Wei Qing and Huo Qubing. But he just happened to catch up with the fatuous old age of Emperor Wu of Han Dynasty and got the opportunity to lead the troops to conquer Xiongnu. However, due to lack of ability, the Huns were defeated, and there were 70,000 casualties in the Han Dynasty. Knowing that he was born to die again, Li Guangli simply took refuge in the Huns and became a lamb. When the news came back, Emperor Wu of the Han Dynasty finally realized his absurdity, so he wrote "The Crime of Luntai" and confessed his mistakes to the world.