I think the reason why Chinese government would execute defected officials, instead of putting them in prison for life, is because historically defected officials often caused very serious losses to the chinese communist party. For instance, one of the most damaging defectors in their history was Gu Shunzhang, who led to the arrest of hundreds of their underground communists (many of those arrested were executed by the KMT government at the time). In those early days, the Chinese communist party was very weak and had to fight for its own survival. So as a result, Zhou Enlai ordered the assassination of almost Gu's entire family, as warning and revenge [1]...

I think this bears a certain similarity to the rationale of that IRA members assassinated their defectors and French executed their traitors in WWII...

It's just sad to see that certain traditions still remained unchanged with the Chinese government (or more specifically, their communist party) ...but at least we can see how much they hate defectors; and we can find some common root of that in all humanity...

Perhaps things will change when they value human life more, which I think they will do when their individual's economic condition continues to improve...When the existence of an average life makes little difference to a society, statistically, life would be socially regarded as cheap...

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[1] https://www.nytimes.com/1991/02/03/weekinreview/the-world-15...