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.