Why are mongols in china being killed? should china give back mongol's freedom?

Mongols are already a "minority" in China, the Chinese people should preserve their very existence and help maintain their numbers. But sadly, that is not what China is doing. Instead, they minimize their numbers, forcing them to do hard labor and the worst part is killing them. The Mongols should retaliate and answer back, they have been oppressed for many years and they are being slowly crippled in numbers so that they are outnumbered.