That means that if you go out for a walk you would be 10 times more likely to run into a friendly stranger who wants to chat.
I've never lived in Manhattan, but I have visited there many times, I would definitely say that walking the sidewalks and parks there, it's mostly anonymous, with less stranger conversation that say the US suburbs.
HN is a really interesting comments site. Maybe this is true of most internet comments sites. I'm not sure because this is the only place on the web were I have ever made comments. But it seems like there is a large demographic that just wants to disagree.
Before you start making comparisons, I'd recommend actually going to China and seeing.
If you just want to look at wikipedia, this is a fairly typical modern Chinese city:
https://en.wikipedia.org/wiki/Chongqing
Yes, very dense, and I can't speak to the public place usage by a broad segment of the population there. But there is no city in the US like this, or any other modern Chinese city.
In general I find the public places in the US to be largely abandoned.
Another related aspect: there are not many publicly visible homeless in China:
https://www.globaltimes.cn/page/202606/1363620.shtml
Making public parks and other places more attractive...
and as european i can also tell you that i am most certainly more likely to talk to someone in manhattan than i would in a european city for example.