"flagged" always means that users flagged it, not moderator action.
And there are a lot of readers who will flag all submissions about US politics, no matter the polarity of the article.
The thing is that dang has generally not unflagged any posts about topics like these in the past, so there's little reason to think the flagging is only a result of temporary inaction by the moderation team. Rather it is a consistent pattern permitted to exist by said team.