Stories gaining traction in the form of comments affects the ranking negatively if it's not upvoted at the same tame. It indicates that people are more interested in voicing their opinion than whatever the submission had to say. If you disagree with that reasoning and want to see lively discussions anyway, you should probably browse https://news.ycombinator.com/active instead of or in addition to the traditional front page.
We've also had plenty of China-related flame wars stay on the front page for longer, so I don't think you can accuse the moderators of applying a double standard compared to other political topics. https://hn.algolia.com/?query=China&dateRange=pastWeek