Spam messages push Wall threads to the top

[jiru]

Story or Context
Recently, a few several years-old wall threads are showing up on the Wall first page because a reply has been posted. The new reply shows as "The content of this message goes against our rules and was therefore hidden. It is displayed only to admins and to the author of the message." Resurrecting old threads is bad manners already, but having such old threads show up on the Wall without any new visible message is annoying.

Idea
Make it so that messages flagged as "against the rules" do not change the thread position. After a message is flagged as spam in a thread, the thread location should be moved according to its latest non-spam message post date.