Protests in some countries might be mild and orderly, or put little pressure to the government and mostly ignored - but this wouldn't necessarily be a sign that the government is more open to protest, just that protests happen to be more "for show" than threatening.

It's also about the culture of police violence. In the US citizen life is cheaper (and one would guess, in China too), judging from the number of police shootings alone, and the excessive police force used for everything and anything, that to have deaths in a protest/riot etc is kinda taken as granted or "the way things are". This extends to protest cop behavior.

In some countries mild or even heavy violence would be tolerated, but a single death in a demonstration could cause resignations or bring down a government. So there are countries with tons of protests for decades involving 10s or 100s of thousands without a single death (mine didn't have a protest death for ages, despite tons of protests and violent clashes and supression by the police), and countries where a protest can turn into deadly suppression almost immediately (e.g. some Latin American countries).

That would likely be even more extreme, wouldn't it? As far as I remember, the protests in HK were massive (as in 5-10% of the population in a single event).