For reciprocity to be in effect, they would need to implement testing of everyone on arrival which is not being done.
Not necessarily. Believe it can be a lot simpler than that.
Would hazard the following "politically correct" response from the UK, or the Netherlands, to Hong Kong.
"Given that according to your verdict our Covid testing produced a failure result, it would be pointless to continue with, for instance, CX flights from the UK to Hong Kong, given that the passengers on those flight will still be tested by our test providers, which, and according to your verdict, are failing in the Covid testing being provided."