Most such stories fall apart after a little prodding. Almost always, detentions are either dumb mistakes, quickly reversed, or the result of actual lawbreaking. Often you read a little further and it's like, "well yes, the drugs I was selling were technically against Chinese law, but..."
However, that is not as fun a conclusion as joining in on bashing the outgroup.
This may be that, and is most likely that for most other countries, but the PRC has a history of disappearances and detainment under false charges, along with elements of the whole Stalin theater. This is why many are immediately more concerned when something like this happens in China than in say, Switzerland.
If they are already there, they either get paid order of magnitude better(yes I’m not kidding some can’t even find job in US) or China brings tons of profit to their business (cheap labor and lower cost ecosystem) such that they accepted the risk.
