Political freedom is not the only impetus for the hundreds of thousands of pro-democracy protesters who this week marched through central Hong Kong.
True, the immediate cause was the Chinese government's recent efforts to assert greater control over Hong Kong. But that is not all of it, by any means.
Tension between citizens of Hong Kong and mainland China has been increasing for several years now, metastasising into cross-border online shouting matches that have made strong impressions on people - and governments - in both places.
Earlier this year, mainland Chinese were shocked by a deplorable incident in which Hong Kong locals sprayed mainland tourists with water from bottles labelled "locust insecticide".
As almost every mainland Chinese knows by now, "locust" is what tens of millions of Chinese tourists who visit Hong Kong annually were labelled in a notorious 2012 advertisement in Hong Kong's most ardent pro-democracy newspaper, the Apple Daily. (It was paid for by 800 donors responding to a Facebook campaign.)
It was an ugly message, and it served little purpose beyond highlighting an intractable cross-border culture war - all the while convincing many Chinese that to be pro-democracy is to be anti-Chinese.
The contrast of world views, and the hate it engenders, is profound.
In the eyes of many Hong Kong residents, mainland Chinese are uncouth buffoons with bulging wallets, no manners and no deference to Hong Kong's status as a more highly developed and cultured gem.
For mainlanders, Hong Kong residents are snobs who fail to accept that they belong to One China.
The skirmishes between the two - mostly conducted online - are depressingly predictable, typically opening with a mainland Chinese tourist committing a petty offence that would hardly be noticed, much less prosecuted, back home.
In January 2012, an online video of Hong Kong residents berating the mainland Chinese mother of a child eating on a Hong Kong subway went viral.
In Hong Kong, where eating on trains is prohibited, the video represented the crude manners and lawlessness of Chinese tourists. Weeks of online vitriol took off from there.
In China, netizens fired back, and a self-described descendant of Confucius went on national television, calling the residents of Hong Kong "dogs" and urging the city to seek help from its "British daddy".
Hong Kong's camera-toting vigilantes remain perpetually vigilant for uncouth mainlanders worth shaming online. The most notorious of these videos emerged this spring, showing a mainland child urinating on a Hong Kong street.
The subsequent predictable debate became so heated, and the hate so palpable, that People's Daily, the official mouthpiece of the Chinese Communist Party, offered an exasperated editorial calling for both sides to calm down.
It was a good idea. But about six weeks later, China issued an official policy paper reminding Hong Kong's residents that their rights exist only insofar as China grants them.
Tuesday's massive pro-democracy protest was in direct response to that paper, and was assuredly political in nature.
But if the spark was provided by China's attempts to control the city's politics, years of accumulated social resentment is fuel. It is a toxic combination, with no apparent solution.
Even if China's leaders offered Hong Kong total independence, the culture war would continue.
That poses a particular challenge to a Chinese Communist Party that counts the return of Hong Kong among its proudest accomplishments.
A softening of its hard line against universal suffrage in the city would go a long way to calming nerves. But it would not do much to the end resentment.
Ultimately, that responsibility is shared by the citizens of Hong Kong. If they hope to achieve a true democracy, with equal rights for all, they will need to accept, and even empathise with, the mainland Chinese who live among them.