We are more mobile and our government is less... disciplined than theirs, our people less responsive to discipline than theirs.
As for mobility, the virus started spreading in China right before Chinese New Year's, which is the largest human migration on the planet where roughly the population of the United States (330M) head off to their hometown and then reverse course 10 days later. China has huge numbers of people working outside of their hometowns and away from their families, while hometown attachment means more to people here (shared local sub-dialects; family history going back centuries; all official gov't matters have to be processed through your official hometown, etc).
The government is more centralized in China, though in an emergency the US Federal gov't has enormous powers if they choose to use them.
Can you imagine a random religious leader on a local level defying Beijing to hold a 1000 person religious event or a regional governor telling the Premier that they're going to continue having their beach parties for the time being?
Religion not a useful example for China, since the gov't is always keeping a close eye on and repressing religious activities.
In South Korea and Iran religious gatherings accelerated the spread of the virus. Iranian officials were very reluctant to close down shrines, where people touch and kiss venerated objects. [for those keeping score at home, the Shiites are more akin to Catholics and Orthodox Christians in terms of worshiping ancestors -- saints in Christianity -- while the Sunnis are more like Protestants in their disdain for images. All stemming from how one interprets the commandment Thou shall not worship graven images]
In South Korea, I was wondering if the larger number of virus cases was the result of the virus spreading at one or two large Christian religious gatherings in Daegu, where I'm assuming more women would attend than men.
As for a large religious gathering in Louisiana, it's just a failure of leadership. Trump waffling on how serious the virus is. The LA Guv not enforcing quarantine laws. The simplest thing is not to allow the meeting place to open on whatever scheduled day. Or you threaten to arrest anyone calling for such a gathering. Very irresponsible, especially since New Orleans has a significant outbreak related to the Mardi Gras gatherings.
I was in Valletta, the capital of Malta for about 5 days of Mardi Gras there (there were two floats that featured Donald Trump, one with Putin as his sidekick, the other he was riding with Uncle Sam). And there were crowds lining the parade routes and lots of people in a fairly small historic area in public, and it was a bit jolting after I had just experienced two weeks of lockdown in Shanghai. The last few days we were in Malta, the viral outbreak in Italy was becoming big news, and you'd look at the Mardi Gras parades and hope the virus wasn't among us. From Italy, from China, etc. The Maltese Carnivale attracts tourists from all over Europe.