Just to put in my 2 cents
Let's not rewrite history here, those that left in 1997 were scared of CCP. That is a fact. We are talking about less than 10 years removed from Tiananmen Square.
I've posted this before, but I will reiterate again for relevance.
As the situation in HK calmed after handover, many of the people who immigrated to Canada as teenagers went back to HK due to cultural fit and much higher income opportunities. The number was so many that my Canadian university would hold special local HK graduation ceremonies. Statistically speaking, the number of HK immigrants leaving Canada have outnumbered those coming in for many years since 2000. Recently the trend has reversed again. Now that they have families they are seeking to go back to Canada once again.
With regards to this 300,000 BNO number thrown around, I think we have to be realistic.
1. Let's throw out this notion of Hanjian. Just because someone immigrates, they are not automatically Hanjian.
2. This is a theoretical number given out by the UK government. Where do they even come up with it? I think I read somewhere this number is over 10 years anyway, so really just overblown, probably not much over natural immigration numbers.
3. The best economic opportunities remain in China, people with a brain know this. How important is politics really to most people?
Going to the Canadian example cited above, really the main driver of returning to Canada is lifestyle (environment and access to education). Some will put politics ahead, but you can't stop them.
I don't think these gestures are anything to be concerned about. Over my lifetime, I have seen nothing but progress in China. Yes, we can argue night and day over this particular thing or that, but you can't argue that life is far better on average. If some people want to pretend in their head that things are worse, I agree that they should be pushed right out the door. However, I don't think it's even close to 100,000's. Brain drain implies having a brain, anyone can see a country that went from being choked with pollution to mandating electric vehicles is trying to move forward. A country that is trying to undo EU after so many years is literally going backwards.