Thank you for a well thought out response which also played in part as to why my initial response to this article was more restraint since as you pointed out in your post all the possible reasons both personal and professional impediments that may have lead Dr.Chen into making his decisions on what's best for his family and his pursuit of science.You know that a lot of Chinese table tennis player play for foreign countries. They are mostly the 2nd tiers in China, or they are the 1st tiers but not the best. But all of them would be 1st tier in other countries. They probably will never have a chance to enter Olympics if they play for China. But they certainly will be able to enter from other countries.
This is ultra competitiveness, but it is no fault of anybody, China has largest population, therefor largest talent pool, largest number of Ph.Ds. Of course some will loose out.
He is not a party member, so going up the ladder in a military institution is certainly difficult if it is possible at all. But if he is so brilliant, why not move to civilian institute.
We shouldn't necessarily believe what he said in the article. Everybody will blame others for their misfortune especially when being desperate like him.
Also, I won't blame him for "betraying". He went to US because there is a open position and the salary was higher than in China (even if he got promoted), his house in US would be multiple times larger than in Beijing or Shanghai, he would be able to have two cars while non in China due to the restrictions on pollution, etc. etc.
This is merely a personal bet on his future and turned out to be a bad bet ruined by Trump's fanatical policy.
In a perfect world, people like Dr.Chen and many others shouldn't be made to feel that their actions could or would lead to their motherland at some form of disadvantage. Their pursuit of fame, fortune, or to simply live their lives in other countries wouldn't be looked into the critical eyes all because of geopolitics.
So I wonder if the duality of purpose can exist without being or causing harm to oneself, to your country and or both. I guess we can never really have our cake and eat it too.