You're right that not every comment which should be moderated actually gets moderated, but this is not because we're secretly on one side or the other. It's because we don't see most of what gets posted here. There's far too much of it to read, and we can't moderate what we don't see. If you see a post like that going unmoderated, the most likely explanation is that we just didn't see it (https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...).
To passionate users, it always feels like the mods are against them and secretly in cahoots with the other side, but this is an illusion (https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...). If it helps at all, the other side has exactly the same complaint, just with the political bit flipped. See https://news.ycombinator.com/item?id=26368875 for a plethora of quotes; they're years old now, but the phenomenon is perennial. Here are a few more recent cases:
HN is mainly left leaning https://news.ycombinator.com/item?id=43559670 (April 2025)
HN has turned into a far-left hive-mind https://news.ycombinator.com/item?id=43214821 (March 2025)
this website is effectively a leftist filter bubble and you do nothing to address it https://news.ycombinator.com/item?id=43146049 (Feb 2025)
a hard liberal-progressive tilt https://news.ycombinator.com/item?id=43136198 (Feb 2025)
a prog-left echo chamber https://news.ycombinator.com/item?id=43133747 (Feb 2025)
an echo-chamber of left-wing lunatics https://news.ycombinator.com/item?id=42576474 (Jan 2025)