I think that if an outright war is raging in the comments, let it run it's course. All parties are willing participants, free to disengage at any moment.
The exceptions should be when illegal content is being shared or illegal activity is occurring (CP, doxxing, etc).
It's always frustrating when a juicy argument gets locked because it's "unproductive". I was having a great time watching it unfold, both sides hurling both creative and uncreative insults, oblivious to how low they are sinking to. It's great!
Something to think about as well is that all of the mods here are volunteers, and frankly if I was volunteering to moderate somewhere and one specific post kept causing issues I’d get sick of it. I honestly believe this is the driving factor for most posts getting locked
Upvoted as it's unpopular even if I heavily disagree with it.
Look at the big picture.
There's a high chance that whatever is causing that flamewar - be it a specific topic, or user conflicts, or whatever - will pop up again. And again. And again.
You might enjoy watching two muppets shitposting at each other. Frankly? I do it too. (Sometimes I'm even one of the muppets.) However this gets old really fast and, even if you're emotionally detached of the whole thing, it reaches a point where you roll your eyes and say "fuck, yet another flamewar. I just want to discuss the topic dammit".
Plenty people however do not; and once you allow flamewars, you're basically telling them "if you don't want to see this, fuck off". Some of those will be people who are emotionally invested enough in your community to actually contribute with it, unlike the passing troll stirring trouble.
Maybe three should be a community specifically for flame wars - a place where senseless squabbles and destructive discord is the norm. It would be a place where people come to fight and see others fight. Think of it as a thunder dome, but for online debates.
I will also upvote because unpopular opinion but I don't agree.
The benefit of the fediverse is that you can pick an instance and communities that align with your moderation preferences.
Personally I'd rather they be locked. Every shit fling pushes the thread back to the top of Active.
Plus, communies have rules. Moderators (in theory) enforce those rules. If there is so much rule breaking the moderators can't keep up, it makes sense to just lock the topic and let the unpaid moderator go have a drink.
Posts should also be locked after a certain amount of time, like a year. It's confusing to have new comments suddenly pop up on an old topic with people not realizing how old the original conversation was and saying stuff like "what do you mean xyz doesn't have this feature? It definitely does because I'm looking right at it." Yeah, that feature was added after the original conversation took place, then you found this old thread from a search engine (not yet a problem for Lemmy). Just let someone make a new post to keep the conversation relevant.
Why are you on a discussion forum for insults? Just go on 4chan or the comment section of YouTube. Or play a RTS with voice chat on. You will hear all the insults you want.