All questions with the notice that I've seen on other sites are closed, which makes sense since these are not considered good questions. So I previously flagged that question with the message If "historical significance", shouldn't the post be closed?, but the flag was declined with the message "a moderator reviewed your flag, but found no evidence to support it".
Are "historical significance" questions always supposed to get closed? Is there a reason why this question is kept open despite having the message?
(Asking here because the basic question isn't specific to Ask Ubuntu.)