Reddit’s userbase is >50% American. Of course you’ll get a lot of Americans reflecting on their own situation,

Just because is, doesn't mean it ought to be. Nothing is forcing yanks to bring up their country when domestic politics of another country is discussed, but they do anyway. That is what people are trying to change.

It’s like going to the German/French/Chinese subreddits and complaining when they talk about German/French/Chinese developments in the context of international news.

Well yes because those subreddits are specifically for those nationalities. Reddit, despite being an American company, doesn't explicitly state it is for Americans. There's nothing on r/worldnews that states the subreddit is for Americans. Yet yanks there still insist on bringing up American domestic issues when discussing other states and excuse it with "well majority of Reddit is American so I can talk about my country wherever, whenever."