Why did Cao Cao kill Tao Qian?

Tao Qian's Ministry Zhang Kai escorted Cao Cao's father and family to take refuge in Cao Cao. Zhang Kai coveted Cao Song's money, so he killed Cao Song and others and went to Wufeng Mountain to become an outlaw.

Cao Cao's Ministry and Tao Qian's son all said that it was enough to send troops to arrest Zhang Kai and take revenge. Tao Qian was an old Jianghu man and immediately realized that Cao Cao would use this as an excuse to send troops to capture Xuzhou. Sure enough, Xun Yu said to everyone, "Why did you want to suppress Wufeng Mountain? Although Zhang Kai was the thief who killed Cao Gong, the culprit was Tao Qian in Xuzhou."

The princes competed for the Central Plains and everyone would be righteous. In a word, Cao Cao characterized Zhang Kai's financial greed to kill Cao Cao's father as Tao Qian killed his father, which is just an excuse for everyone to see.

Cao Cao used this trick well. In fact, Cao Cao could use it as an excuse to separate Tao Qian from Xuzhou people, find out or slander Tao Qian's other crimes, and then arrest Tao Qian and his son on the pretext of revenge and killing the people, instead of killing Xuzhou people indiscriminately. Cao Cao's strategy of not dividing the enemy was really a defeat, which actually put Cao Cao in a passive situation of immoral behavior, which also led to Liu Bei taking over Xuzhou easily.

With Cao Cao's treachery, Tao Qian and Cao Cao were talking in the moat less than a few meters apart, and Cao Cao would capture Tao Qian on the spot. Cao Cao only needs to say to Tao Qian, "Didn't you say that you didn't kill my father? I want to hear how my father died. If you really didn't kill him, there is still room for discussion." When Tao Qian heard that there is hope of survival, he must be condemned to explain that Cao Cao only needs to dismount and walk into Tao Qian. As soon as they get close, they will kidnap Tao Qian and then invade Xuzhou City. What dark archers in the city are all made up by the director! Why, I, Cao Cao, originally came to attack the city. It is understandable that the other side is well-defended. What's the accident? Now I hijack Tao Qian, and I can attack Xuzhou in a few minutes. This scene just didn't happen, it was just the director's wishful thinking. When Liu Bei brought thousands of military forces to Tao Qian's rescue, Cao Cao said, "Let's retreat slowly and lead them to attack", which is a super joke. Cao Cao has at least 5, military forces, while Liu Bei has only a few thousand military forces. How can Liu Bei attack Cao Cao? Liu Bei's goal must be to retreat to Xuzhou.