It's the moderators' or the admin's decision as to when a thread should be closed. I am perfectly content with that. I imagine and expect that the decisions are appropriate.
At the same time, it would be nice if the criteria of that decision is disclosed.
The disclosure can be one at a time per case or as general.
That way we can be more careful to keep the friendly atmosphere.
Personally, I see bashing of skaters (or of a certain skater more often) that are let go to be more of an issue than the excessive exchange of irritation or anger.
... I think so, according to, or even without, the guideline.