>>> Barring them from leaving the country feels a bit sinister for people who haven't been accused of committing any crimes.
This is standard operating procedure for the CCP. They are a truly ruthless, sinister group who have no scruples about ensuring compliance and using leverage on behalf of Chinese interests. Just look at what happened to Jack Ma.
Oh come on. Look what happened to Russian enterpreneur, Pavel Durov in France, and what happened to Julian Assange and to Edward Snowden. It's the same thing just wrapped in different colored package. You don't cooperate with the government, you have some suffering.
They are good actually.
Jack Ma is fine. If that's what you mean by ruthless then it's not really a big deal.
Gemini, Give me examples of people that the US has retained passports pending investigations
It's standard procedure in every country for some investigations.