Edit: I wrote an entire reply and then realized you were asking about the thread before that comment, not about how to respond to it. So I should try to answer the question you actually asked.

The one thing I'm aware of that you can do, to help dampen the nationalistic emotions and flames that spring up around this topic, is to scrupulously make your comments as factual and as neutral as possible. If you let your frustrations leak into your posts in any way, readers who disagree will take that as license to respond with 10x of their own.

This isn't easy to do, but it does help. It's not, unfortunately, a sufficient condition to avoid getting flamey responses on this topic. I wish it were, because it's a big problem and becoming worse. (I even made a specific list of moderation comments about this because the issue comes up so often: https://news.ycombinator.com/chinamod. There's no other issue I've felt compelled to do that about so far.)

Bad as the situation is, though, I would not underestimate the persuasive power of a commenter who's able to keep their cool and stay flamebait free in everything they post on a divisive topic. It's a judo move in the end because the ones who respond with flames effectively single themselves out as not having good arguments. But the judo move only works if you preserve the asymmetry—i.e. if both parties are flaming, then they're discrediting themselves equally and it's a wash. If only one party is, then the other one wins by default. It doesn't feel that way in the moment (I feel the tug to respond-in-kind as much as anyone!) but when you go back and look at those threads later once the ashes are cold, it's quite clear.

Edit 2: There's one other thing you can do to dampen flaminess and increase the persuasive power of your own comments, although it's not always easy either. That is to find some point of relational contact with the person(s) you're arguing with. The most straightforward way to do this is to find something to agree with in what they're saying; or, failing that, to find some way of supporting the positive intention behind what they're saying.

The reason this works is that when people are arguing, they're inevitably arguing on two different channels simultaneously: (1) disagreement about the topic—that's the obvious one; but also (2) what each person thinks of the other. When the disagreement in channel #1 is so stark that neither party can find anything to agree with or respect in what the other person is saying, it inflames channel #2 and starts to feel like a struggle to defend one's self against attack. In other words, it starts to feel like a fight to the death (this is absurd on the internet, but this stuff all relates to hard-wiring from long ago). Survival instincts start to get engaged. When people feel like their survival is at stake, they'll resort to literally anything. In internet forum threads, that means lots of the worst kind of flamewar, including "are you being paid to do this" and much worse.

However. In a way similar to the 'judo move' I mentioned above, you can turn this to your advantage—and not only to your advantage, but everyone's advantage, by finding ways to reduce the pressure on channel #2. That's what I mean by "finding some point of relational contact". If you can do this, you're basically sending the message "I don't want to kill you" on the side channel, or—less melodramatically—"I'm not trying to vanquish you, I just want to find the truth together". When people negotiate that successfully on the side channel, the discussion on channel #1 (the actual topic) magically becomes more meaningful and interesting. But of course it has to be done with subtlety—not in the manipulative sense, but just in a way that genuinely respects the other person and allows them to feel heard and save face.

This is stuff we have a lot of ways to take care of automatically in person, without even realizing we're doing it, but because things like tone of voice and body language aren't available online, it's easy to fall into the worst interpersonal situations very quickly. Part of the challenge of developing a good forum culture (which is what we want to do here) is developing a new set of techniques that can map what we do instinctively in physical space into virtual space, in a way that leads to more complex and more interesting conversation. I don't think this is easy at all, so I don't think it's so terrible that it's taking us decades to get there. I do think it's a good idea though.

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Honestly I think the only thing it really made sense to do with that one was to remember and practice this site guideline: "Don't feed egregious comments by replying; flag them instead." (https://news.ycombinator.com/newsguidelines.html) ...which is our euphemism for "please don't feed the trolls", which strikes me as probably the wisest thing the internet ever said.

The reason I say that is that there literally wasn't any information in the comment to rebut—just a smear ("are you paid to do this") and a bunch of name-calling and innuendo. If you try to rebut it, you're forced to go to a non-factual, name-calling level just because there was nothing else there.

Of course it's frustrating, not least because it takes time for enough flags to build up and/or moderator attention to get attracted, but in the end the system takes care of these things fairly easily. You can always email hn@ycombinator.com in egregious cases to speed that process up.

(Separately, in case anyone feels I've been too harsh here: I don't mean to pick on chx - it's easy to make these mistakes when emotions are high. But important to learn not to.)