The submission was flagged by users. Moderators downweighted it the way we downweight all sensationalist flamewar articles (if we didn't, they would always be all the top stories on HN). But it is the user flags that buried it.
Articles and sites like this one are off topic for Hacker News. We're looking for articles that gratify intellectual curiosity, not ones that gin up flamewars, let alone nationalistic flamewars. Submissions to Hacker News need to be much, much more substantive than this—most of all on divisive topics.
This is obviously a single-agenda, highly politicized site; we ban all of those, regardless of their politics. We also ban accounts that only use HN to promote their own site (https://news.ycombinator.com/submitted?id=subsonico). Indeed, on second look, it's clear that this account and this site have simply been spamming HN: https://news.ycombinator.com/item?id=18381256, https://news.ycombinator.com/item?id=17834767. We should have caught that a long time ago. (Edit: and even the current article turns out to be blogspam from another source.)
We don't moderate stories about China differently than any others. HN moderation standards are consistent to the point of tedium. There is inconsistency in practice, but only because of the quantity of material that appears here—way more than we could ever hope to read or even see.
Users with strong opinions are quick to convince themselves that they see bias, because the stronger your feelings on a topic, and especially the more you dislike something, the more this affects what you notice. Plenty of stories critical of things in China spend plenty of time on HN's front page (e.g. https://news.ycombinator.com/item?id=19493033 has spent most of today on the front page). If you've noticed those at all, I'm sure they didn't attract as much of your attention as this one getting flagged. Readers with opposite views to yours feel equally certain that HN is heavily biased against China—and frankly, based on the stories that appear here, they have a better case for their claim than you do.
"Sam Altman's China strategy", whatever that is, has nothing to do with HN. Our sole "strategy" is to maintain an internet message board that doesn't choke to death on its fumes while burning to death from its flames. That is already a feeble enough hope that we have no bandwidth for anything else.
Edit: having just taken a look at your comment history, I'm dismayed to see that this account has also have been using HN exclusively for nationalistic and political battle. As I'm sure you know, this is not allowed on HN and we ban accounts that do it. Worse, you appear to have done it numerous times before. When people create accounts to break HN's guidelines like that, we eventually ban their main account as well. If you'd please review https://news.ycombinator.com/newsguidelines.html and use HN as intended from now on, we'd appreciate it.