HN aggressively mods away a lot of the stories which draw the most attention on local news sites.
Sanitary is a good way to describe it to be frank. It’s relatively cordial but also not someplace you come for unconventional opinions or out of the box thinking.
Whatever you do, don't mention the war!
Meta-moderation, which also required oversight to minimize abuse.
I suspect that the relatively narrow targeting helps as well. General news sites have a much broader audience with (generally) less subject-matter familiarity than HN.
And most stories here are far less controversial than most news stories these days.
The old Slashdot comment system before the original creator left worked very well. It was proud to say that the only comment they were forced to delete was one that criticised Scientology. That was because they took Slashdot to court. Users moderated comments with a set amount of mod points, usually only having 5 points to moderate up or down at a time (every few days I think for people with excellent score), there was metamoderation there as well, user metamoderation mind you. Not sure if metamoderation was there at the start, but the comments I generally saw were generally quite good. It was great to get various viewpoints without all these people trying to stop people saying their piece like we find all the time today. Not that no comments were removed, comments were hidden if they were below a specific score that you set. You could set the score to -1 if you wanted and see all the comments, and it was nice to do so sometimes. Note that it really did work like a democracy to show what comments people really thought were worth upvoting. It worked. Now with the new owners there is a link to flag a comment on the bottom right of each comment. Sad.
The ability to quickly flag posts that attract partisan back-and-forth helps a lot. That doesn’t work out quite as well for a newspaper, where virtually every story can relate in some fashion to politics.
Because people here wrap their offensively stupid opinions in polite language.