I'm happy to admit mistakes (and correct them!) but this is inaccurate. We don't edit titles to put our own personal spin on a topic, which is what the word editorializing means. We look closely at the article itself to find what it is actually saying. If we do replace a title, we replace it with representative language from the article itself wherever possible. This has been the case for a long time:
https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que....
That does involve some interpretive judgment—because why pick one phrase rather than another—but less than you might think, because nearly every article has a point where the author says what they're actually writing about.
We never do this to convey an opinion of our own. We don't much care what people think or what an article says. We care whether the title accurately represents what the article is saying, and does so in a way that isn't baity, because that is the biggest influence on discussion quality.
The submission you guys are bringing up (https://news.ycombinator.com/item?id=31396861) illustrates the point. "Why I no longer recommend Julia" is a baity title, because it doesn't say anything specific about why. It's just a pointer that says "I boo Julia". "Boo $language" is for sure flamebait on this site.
Such titles generate threads that are just generic boo-vs.-yay ventings between people who like $thing and people who don't. The substantive points of the article are lost under such a title. This is not true on the original blog, because there the title is just the first sentence, and any comments show up only at the end. But it's definitely true on an internet forum where the title is the entire representation of the article for most readers and commenters.
For that reason, we chose to change the title, and for that we looked at the article (https://yuri.is/not-julia/) to find where it says what it is actually about—the "representative language" I mentioned above. This was not hard to find—it's in the 3rd, 4th, and 5th paragraphs of the OP. Particularly the 4th, which reads:
My conclusion after using Julia for many years is that there are too many correctness and composability bugs throughout the ecosystem to justify using it in just about any context where correctness matters.
That's the article's own summary of what it says, so we made it the title. Basically we followed the pointer and replaced it with what it points to.