Why was the other thread removed? It was #1 on the main page.
„Other factors affecting rank include user flags, anti-abuse software, software which demotes overheated discussions, account or site weighting, and moderator action.“, see https://news.ycombinator.com/newsfaq.html
<https://www.righto.com/2013/11/how-hacker-news-ranking-reall...>
It's not perfect, but it really does often correctly identify flamewars. If you feel a post has incorrectly triggered the flamewar detector, email mods at hn@ycombinator.com.
As I write, this thread doesn't trigger the criteria.