My understanding is that flagging does not imply moderation. When enough people flag a comment, it becomes dead automatically. There is, separately, the case that a moderator “kills” an unacceptable comment, but then it only appears as [dead] I believe (unless it was also being flagged by people). Someone correct me if this is wrong.
Moderation by the community is still moderation.
Well, you can call it that, but there is not a singular will or policy behind what is getting flagged, and the HN “community” isn’t homogeneous. HN users can also “vouch” to counteract flagging. It only takes a single vouch to un-kill a comment.
The value of "enough" is a moderation decision made by a human.
It’s not a decision made per individual submission or comment, I think. Of course, the specific automated mechanism exists because some human decided to implement it. My point is, in the case of the flagging mechanism, it’s not the moderators who are deciding based on the contents of the submission or comment.