Seems like a weird position; it's repeated so much because it's a massive problem that needs all of the attention it can get. I don't see why "repeating" anything is a reason to edit titles.
People sometimes feel that if a story doesn't make HN's front page or gets downweighted or flagged from HN's front page, that's because moderators or the community are saying it is unimportant. This is not true at all. Many topics are far more important than anything on HN. An odd, obscure topic is more likely to be on topic than a world crisis. There was just a thread about John Cage's mushroom hobby [5], of all things.
This leads to a somewhat complex dynamic because having an interesting site attracts a high-quality audience, and people then want to use the site to get stories they care about in front of that audience. Sometimes their motives are merely commercial, but sometimes it's because the story is big and important and they're passionate about it. It's easy to declare the commercials off topic, but when it comes to the important stories, that's when we need to remember what HN is. Maintaining an odd sort of site that goes against the default forces of the internet takes a lot of focus and you have to say 'no' a lot. If we start breaking the intended purpose, HN would quickly cease to be the kind of forum it is today—it would become a site for the same few important and/or most controversial stories, repeated over and over. Not only would that make HN totally different, it would probably kill it, because such a situation would be unstable: the current audience would largely leave, because HN would no longer have the quality that attracted them here in the first place. No one is claiming that intellectual curiosity is the most important quality or motive—but it's uniquely what this place is for, and one has to know what one is trying to achieve and what one is not trying to achieve.
[1] https://news.ycombinator.com/newsguidelines.html
[2] https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor...
[3] https://hn.algolia.com/?dateRange=all&page=0&prefix=false&so...
[4] https://hn.algolia.com/?dateRange=all&page=0&prefix=false&so...
[Edit]
I wish I didn't have to continually edit myself but originally I used the term "editorialize" and I thought it had a more broad meaning of "exercise editorial discretion". While there is still an opinion involved in the edit. Something along the lines of "users of this site will already know X so it isn't part of the diff" I don't think it meets the stricter definition of editorializing. "Not part of the diff" is still cited as a justification for editing the title that I don't see covered in the current site guidelines.
Arguing against including the whole title in this case makes me much more curious about how you make decisions and why than anything else.
You're essentially saying "I'm removing this because I don't personally like it" when it has no other reason to be removed...
> Climate change is bringing tourism and tension to Longyearbyen on the Norwegian archipelago of Svalbard
The article's first paragraph is how homeowners are noticing cracks in the foundation due to the terrain under their houses receding due to climate change warming the otherwise permafrosted ground.
The article's third paragraph pretty concretely discusses exactly what is happening to the temperatures there.
The entire article is about climate change. You've removed a very important part of the original title for (in my opinion) some philosophical nonsensical reason, ultimately changing the meaning the author intended.