So I should preface this by saying I am a poster at /r/China so I might be slightly biased.
/r/China is the general discussion subreddit for all things related to the People's Republic of China. The posters are predominantly American expats in China with most of them being English teachers. Due to the high stress environment of day to day living in China, most are quite burnt out at this point. So the sub as a whole takes on a negative outlook with a fair amount of vitriol in the comments.
/r/YellowPeril is the Asian American version of /r/ShitRedditSays/.
/r/AsianMasculinity/ is the Asian American version of /r/TheRedPill/.
So as you can see, both subs would take offense at the negative portrayal of China by non-Chinese expats.
What set this powder keg off is certain members of /r/China creating /r/CaucasianChinese/ as a parody of /r/AsianAmerican.
So now the Asian Americans who don't live in China have /r/Sino,
and the Americans in China who aren't ethnically Chinese have /r/China.
The funny thing is very few Chinese nationals actually use either sub.
ここには何もないようです