Did they hurt their own people and troops for their own purpose.
That should not never happen again ... There's another way, always .. better way
It called sacrifice.
So why need it ? National economy decide government politics, politics decide whether need War, War decide whether men died on the battlefield.
If we stand higher to view the reason of Sino-Vietnam War.
During 1970-1980s it's still COLD WAR most nations selected one side the West or the East, China against former Soviet coz Mao and 1969 Northern border dispute. Although Mao's time China did not openly stand together with West, there was a signal U.S President visited Mao in BeiJing. After Deng pro-west and he believed Russian can not help China and only the West can provide funds & technology to help poor China development,
that's China national interest to make Mr Deng to choose a good useful side - the West in the COLD WAR. At that time in Europe NATO face threats from WTO, in Asia former Soviet had invaded Afghan and ur Vietnam invaded Cambodia,
Cold War in 1970s~1980s early it's a very good situation for Soviet and her alliance nations. As a new & odd friend (China only socialist country) in West alliance, Mr Deng decided China diplomacy should do something to obtain trust from West alliance. Foreign War is the only thing poor China could do in 1979, and another reason is China dislike ur Vietnamese idea of Indochina Federal, it also will be conflict with China national interests in Southeast Asia.
For West's economy and technology supports and For against ur Inochina Federal plan, Mr Deng decided China join a foreign War with Vietnam. Of course there must be men died in the War, Mr Deng is a hard man but he has eagle eyes and clear head, except dead Chinese soldiers he know a limited war can not hurt China anymore and what benefits China will get from the West through Sino-Vietnam War. After Sino-Vietnam War huge foreign investments from the West will bring money and new technology to boost China economy development.
Inside China, Chinese called Mr Deng as a great militarist and economic chief designer. I think Mr Deng's achievement is the old man saw through the key of WAR,
WAR just served for national economy. Without a strong economy, ur country finally will lose in world game.
Chinese believe our soldiers lost in Sino-Vietnam War is for our economy development in 1979 and 1980s, it's Chinese sacrifices for building a strong & powerful China.