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Many other countries have stopped Chinese nationals from entry.
Why haven’t we?"
The photos and story here show part of the answer.
https://www.dailymail.co.uk/news/article-7947463/PICTURED-Inside-Coronavirus-quarantine-air-base-California.html
At least some of the countries trying to bar Chinese nationals from entering are lacking the resources to take care of coronavirus patients. China is now trying to generally stop people from leaving, at least in some parts of the country. Many Americans, Brits and others are kept there by the "lockdown." For example, at least one plane was prevented from evacuating Brits. The U.K. is trying to make a deal with the Chinese to get those people out with military medical personnel on a flight.
I don’t think we should depend on the Chinese authorities to keep people from leaving China. It seems it would be in their selfish interest to allow as many to leave as possible, who have visas to enter the US (Chinese nationals who may have green cards to work here, or Chinese Americans who had returned home for the new year holiday). If they are here, that many less for them to take care of.
We should be making our own policies on non-entry, not hoping they (communist Chinese party officials) will do the right thing. They aren’t well known for that.....