China desperately requires dollars to keep its debt problems floating and to interact with the global economy (relatively little is settled in Yuan outside of China's borders). Without a steady inflow of dollars China cannot function normally; their economy would seize up.
Hong Kong is a critical inflow port for US Dollars into China's economy and is largely spared from the tariff war.
This is why Hong Kong is so important to China right now, and it's also why China has been so careful in suppressing the protests (by their standards). China is afraid of the US changing Hong Kong's special status. People often don't think China can be swayed: the US slapped currency manipulator status on them, and they immediately backed off from letting the Yuan sink, carefully pegging it just inbounds near the 7 line.
Not to mention that many CCP members have a lot of investment in Hong Kong, a collapse of the HK economy, should the PLA be deployed, would be quite problematic.
But I generally agree with your observations.
Culture is more than the rack (or tailor) you buy your suit from. If you choose to wear one. Things like personal space and not spitting in public and not having to kowtowing to whomever is the current President, are things some hold dear. Others may not. Other still, may look to the past and ask: what started on 15th April, 1989 and ended on 4th June 1989, in Tiananmen Square, and elsewhere in China?
Personally I think that ship has long sailed and it's not particularly anyone's fault.