i) It's basically because there aren't many people who travel between France/Spain & HK, relative to UK & HK.
The high risk country labelling is more about putting the financial and logistical burden of a positive onto the individual rather than the HK govt and acting as a disincentive to travel. Hk can bear the low numbers (no direct flights) from France and Spain. There's also the potential politics of further punishing students, the main group likely to return to HK from the UK.
But as the partner of a French girl looking to go back to France next month, there is now a serious risk of being added to the high risk list whilst there . . . which doesn't help HK much at all, but would cost us a lot of unnecessary expense and stress upon rtn.
ii) A good question - a well placed lie and indirect flights may well be the solution....