And I respect the ideology of once some someone is a citizen, they should have full rights. Though ideology and practicality do not always meet efficiently and in something like this I feel practicality is needed.
So circling back for clarity, my point was I suspect (note, saying I suspect not know) there is higher risk of a naturalised citizen harbouring loyalty to their origin country and/or being more easily manipulated via family ties etc. This would vary by country and circumstance so is not black and white but in this situation where you know Chinese agents are very active, I find it amazing, for right or wrong, an agency would take that chance. And with hindsight, this is a very correct view.