Should we have vouch for stories that haven't been marked flagged yet as well? I will search for HN's ranker formula but right now, it shows this story in 8th place to me. The upvote/time would put it on top, so I am guessing either most upvotes are old and there is a decay involved in ranker or it is also being flagged. It could also be an auto flame war detector pulling it down, HN has one based on upvote/comments of the post, I am not sure if there is one which considers voting within comments itself.
This is the critical point. Today, users can "vouch" for [dead] stories, but can't vouch for [flagged] stories until they get flagged so much that they convert to [dead].
The other "Tank Man" story was flagged, but never quite dead, so users couldn't vouch for it; from users' perspective, it appeared to simply disappear.
Allowing users to vouch for the other story would have helped considerably.