I think you've picked a bad example to make this argument about. "China is a scary country" is an unsubstantive negative statement about an entire country. It isn't nuanced. It's not qualified in any way. That easily falls under whatever moderation rule we might apply.
People often seem to think they're making nuanced factual statements when they're actually making blanket emotional ones. Those have degrading effects on discussion here when they're about entire nations, entire classes of people, and so on—and they're easy to avoid if one chooses to.
Part of the issue is that HN threads feel like intimate conversation—which is wonderful and something we consciously cultivate. But it's all fully in public and the audience is large and highly international. Because that gap isn't obvious, it leads people to say things which might be inconsequential in a small group, but are just the opposite here.
It only takes a little objectivity and/or empathy to get what it must feel like to come to HN and encounter putdowns of one's country or one's demographic. That's not cool, and fortunately it's not necessary, so commenters here are responsible for clearly disambiguating their comments from that.