> citizens of the USA often make similar remarks about their own country, and that these remarks are seen in good light on HN

I think this perception is likely affected by cognitive bias, i.e. you noticed some cases of this that stood out for whatever reason, and it formed your perception of HN in general (in this respect). From my perspective, similar remarks about the US are just as much flamebait—even more so, because there are more people who react to comments about the US than about Spain—and we moderate them just as strongly.

I imagine I made the point already, but just to be clear: we need you not to post like the GP comment, not because you owe nationalists better, but because you owe this community better. The container is fragile and we all need to take care of it, so we can keep having a community where interesting things appear. The alternative is scorched earth, which is not interesting.