Many many other top-level comments are similarly non-specific to anything in the article and more or less generic springboards. But you didn't respond to them in the same way. shrug. That DEI policies were an form of racism/sexism is not an especially novel or heterodox opinion. Opinions aren't facts and can't be substantiated. And I think agnostics and even DEI promoters can correctly infer why detractors would perceive these policies to be racist/sexist in nature without elaborating in depth.
You're probably right about other comments but I'd have to see specific links to be able to say anything about them.
If you see a post that ought to have been moderated but hasn't been, and therefore makes you feel like moderation is inconsistent and unfair, the most likely explanation is that we didn't see it. We don't come close to seeing all of what gets posted here. There's just far too much. You (or anyone) can help by flagging posts that break the guidelines, and in egregious cases, emailing us at hn@ycombinator.com.
It's true that moderation knobs would probably be turned up on comments like "DEI is just racist/sexist", not because we agree or disagree one way or the other, but because those are flamewar clichés. The main thing we're trying to avoid is repetition, especially flaming repetition. What we want here is curious conversation, which seeks new things to look into and talk about.
Rayiner writes substantially the same comment: https://news.ycombinator.com/item?id=42663406