Because Genghis Khan abolished the custom of bride kidnapping. The first time I saw this was when I was a young man, and it was the first time I'd ever seen a woman in the world," he said. Because Mongolia is born on horseback, and then in order to prevent the tribal men and close relatives to intermarry, so there is an explicit rule requires the Mongolian tribes in the men and the outside of the woman intermarriage.
However, the system of bride kidnapping allowed many young married women from outside to be snatched away. Genghis Khan abolished this custom in order to unite the tribes. The bride kidnapping was a very barbaric custom that did not follow the women's wishes at all. Many women had families in another tribe, but were unable to join them because they were taken away from them.
This shows that Genghis Khan was a very enlightened king. No wonder Genghis Khan was able to unify so many regions afterward. The men of Mongolia, a nation of people, were tall, powerful and unpretentious, so from time to time wars arose between tribes as they looked at each other unfavorably, and would decide who was right and who was wrong by dueling.
While this way of this thinking can be attributed to the fact that these people are relatively simple. But this simple way of settling things has created many, many wars between the tribes. And they took this simple and rough thinking of the males and forced it on the females, leading to incidents such as bride snatching often occurring between the tribes.
After the abolition of this bad custom, the Mongolian tribes had more respect for Genghis Khan. All the women danced with joy, which showed that Genghis Khan was a very enlightened monarch, he knew how to solve the problems of his people, he knew how to sympathize with the people, is a good Khan.