The UK should have given the people of Hong Kong full citizenship before handing control back to China. It's a disgrace that we allow China to mistreat the people of a former British territory.
The people of Hong Kong should have been just as entitled to self determination as any other people, and establishing full democracy and self governance would've been the ideal solution. But China apparently made it clear in the 60s that it would retake the territories with force if Britain tried to do that, so it was forced to remain a territory until handover.
While some fault can be given to the UK for not pressing it harder, China was not willing to accept that (for ethnic Chinese; non-ethnic-Chinese weren't granted Chinese citizenship).
I'm not familiar with the case surrounding other British territories however this is one case that is still within recent living memory and not something that happened 80/100/200 years ago. Many of those within Hong Kong who were given BNO passports are still quite alive and wont be going anywhere for a long time. I also consider the people of Hong Kong to be more British than French/Dutch/German.
Who said I only care for people who are more British? You seem to be reaching. You could apply the same logic to those who care more for their family than a stranger and justify calling them gross/selfish. It's quite silly.
The husband and son of the 'chief executive' (ie Beijing puppet) have full UK citizenship (as well as the previous chef executive too).. The British should revoke all these government officials' citizenship (And their family) in fact.
To my knowledge, while this is not the case for all HK citizens, special considerations were given to professionals (at least, medical professionals), who wished to obtain UK citizenship.