Sorry this reply comes a few days late. I don't agree with some of your points but I appreciate your effort to let folks here know about the perspective of many HK people.
I think you are making unwarranted generalizations in the way you describe "the mainland Chinese" as well as when you say "we" to speak for the people in HK. I'm a HK citizen myself and I do not agree with what you expressed here, although I can fully understand where these feelings come from. I also know this sentiment came from many people in HK, not just from you alone. On the other hand, I want to offer my criticism because you’re not just expressing feelings, you are making claims about a group of people, and the claims you made here are, IMO, unsupported and biased.
Yes, some of the incidents you described could be real and accurate (there has been lots of false rumors designed to fuel hatred, so I'm always skeptical when reading, but I know some are true), but do they support any claim towards “the mainland Chinese” as a whole? I don’t think so. Have you thought about how many incidents of inappropriate behaviors were shown among the tens of millions of mainland tourists that goes to HK per year? Have you put the scale of that number into consideration before you label a group of people? Now if we blow up the number of US tourists to the same scale, and with the same SES diversity, do you think there will be significantly less “problem cases”? Having also lived in America for a number of years, I doubt it. This is not to say the Americans are as worse as the mainland Chinese or that they’re both “inferior” to HKers in manners, it is just a simple fact that in every large enough group there will be people with problematic behaviors even though the rest majority could be regular, well-mannered folks like you and me.
Unfortunately, most people are not trained to recognize this. Confirmation bias and selective attention are hard wired into our brains to make us think quicker but not necessarily accurately. The media (both traditional and social media) took advantage of this to create and amplify negative sentiments because they naturally generate more attention and therefore have a competitive advantage over other news. Someone acting like normal is never news, someone acting like a prick is, especially when said person fits into a target stereotype for discrimination. Many people are going to think oh geez look at how disgusting this mainlander is, with a focus on that mainlander label while conveniently ignoring the vast majority of the group who acts respectfully. Then things get more complicated when negative sentiments develop into aggression, and aggression elicits aggressive reaction. Why do some mainlanders make negative or insulting comments towards HKers? Many of those were reactions to insult, discrimination, and arrogance that some people in HK have displayed to mainlanders. In turn those in HK who feel insulted develop more hostile attitudes, and the vicious cycle goes on. None of the insult from either side should be justified, but you need to understand that they both happen for a reason, and it’s not because one group of people has less moral integrity versus the other group. Don't ask for who started it either because what really started it is a conflict of interest plus human's natural tendency of intergroup bias. If an interpretation stays at the level of “they disrespect us first therefore they don’t deserve respect”, it’s never going to resolve anything.
And trust me, it’s not the mainlanders who have the most need to pursue a resolution. By all means, HK’s future depends much more on mainland China than the other way around. I’m very disappointed that many HKers never sees the big picture as they focus on all the issues at the tip of their toes. What does HK have in the long-term to compete with Singapore or Shanghai or even Shenzhen-Guangzhou-Foshan when you look at the structure of its economy? Nothing I can see to foster sustained growth, and putting all your eggs in one basket of virtual economy for a multi-million population is outright dangerous. Yet many people in HK were deceived by the phenomenon that hordes of mainlanders still go to their city to buy stuff, to give birth, or to become an immigrant. It create a false sense of superiority that HK is a place with a better future, others should beg us for our goodies and we don’t have to ask them for anything. In fact we want to keep our goodies for ourselves so they should get the hell out. It is true that HK has many unique benefits that mainlanders desire which is why many of these conflicts started, a conflict of interest and impact to daily life created by supply and demand between two very disproportionally sized markets. Too bad this sense of being in demand has nothing to do with the city’s long-term potential to thrive. It is completely righteous for HKers to complain about the impact to daily life from the excessive number of traveling mainlanders and look into policies to protect their own interests. But by taking a step further to demonize mainland Chinese as a group, we are practically killing our competitiveness.
This is why I don’t like attitudes such as “with this argument you’re not going to change the mainstream opinion in HK” or “You made us behave this way, it's your problem”, it's a sign of arrogance. Who are we to demand others to convince us to make the right call for ourselves? We and only we are responsible for our behavior and our future. There is no way for any country or city to really become successful if its citizens are all about having a sense of entitlement rather than a sense of responsibility. Too bad what I see in today's HK are mostly about the sense of entitlement.
If you’re into multicultural psychology you probably would have learned about the identity development models. The general model by Sue and Sue suggested five possible stages of identity development for cultural/ethnic minorities (including immigrants):
Conformity
Dissonance and appreciating
Resistance and immersion
Introspection
Integrative awareness
There’s also the more specific theory of Kim’s Asian American identity development model
Ethnic awareness
White identification
Awakening to social political consciousness
Redirection
Incorporation
Despite the discrepancy in some of the steps, they both described the phenomenon of people identifying with the mainstream culture and distancing themselves from their culture of origin. This is common when people’s concept of identity was preoccupied with minority oppression, and they struggle to become accepted by the majority. It is not diversification but conformity when the sense of identity is characterized by a fear of being alienated. From my observation, many people who refuse to identify themselves as Chinese (in addition to being HKnese or TWnese) did so to distance themselves from the mostly negative stereotypical image of China which was common in Western societies. Thanks to the dominance of western values in the media, today this may also happen in non-Western countries. It is not that they lied to blend in, but they truly don’t believe they're Chinese because they have internalized those biased values associated the word Chinese, and they can't identify with those biased values. The more difficulties they experience in acculturation, the more strongly they will oppose to a Chinese identity, and the easier they may become agitated when being identified as a Chinese. In this case agitation is driven by stress, and stress is driven by fear. On the other hand, those who lives as an ethnic minority but had a relatively easy time blending in (usually for second or third generation immigrants) rarely show resistance in admitting their Chinese roots, their problem is they may have little knowledge about these roots. So I have to say a better word to describe it is conformity rather than divergence.
True divergence happens near the final stage of identity development which is integration/incorporation. A mature and healthy identity is always unique because it is inclusive and integrative based on all the person's experience and background. One can’t become more unique through exclusion (denying the Chinese/American/HK/TW part of their identity), because the more you take away the hollower you will be. People with a healthy and integrated identity is more capable of accepting a multicultural root and they will have less stress about not being recognized by others. If someone doesn’t know about your culture and makes bad assumptions, it shows their ignorance, not yours. So why deny parts of who you are just to get an people's recognition? Unless social acceptance is still the main challenge. This is mostly consistent with what you described, but I'm pointing out that in terms of identity development this is not somewhere you want to stay forever.