I mostly click on HN articles via Facebook, but I don't actively engage in discussions. I also happen to come across a lot of discussion on Chinese social media, like zhihu.
The news has been trending on Chinese sites for days, and when it's something as sensational as "China ranked lowest in global HONESTY study", people started to ask why, many went ahead and read the paper, found potential flaws in the design of the study, and wanted their questions answered. And when valid questions are not yet being addressed, many start to question the motivation behind this paper; the motivation of using labels like "honesty", that clearly has moral implications; the motivation behind Science publishing it, etc. Did the author exclude Japan because the result differed drastically from what was expected? Did the author include China because the result conveniently confirms the stereotypes? Are there any ethical concerns for such studies? After all, this seems to be a study about how likely it is for hotel staff to email the owner of the lost wallet in different countries, but it is being phrased into something much bigger.
Not saying those are real motivations of the paper, just emotions and speculation running wild in Chinese forums, then people get a bit angry, because they feel it's unjust, and they want to look for ways to communicate outside of Chinese social media.
Anyways, thanks for still keeping the discussion open. Most just want to have their voice heard, as they feel very, very strongly about it. And a possible explanation of commenting in Chinese is to force native English speakers to look up the translation, some sort of reference to how the study is conducted in English, even in China.