Why destroy the Xiongnu? Is there any harm in it?

As a nomadic people, the Xiongnu were naturally enemies of the farming people.

The origin of nomadism and the emergence and evolution of nomadic countries have played a decisive role in the development of human history.

Nomadism and farming have been in opposition to each other and interdependent for a long time in the development of human history.

All historical phenomena such as wars, plunder, marriage, and mutual trade seem to illustrate one theme: survival and wealth are the reasons for the rise of nomadic countries.