On SO recently a poorly-asked question received this comment:
410 points and you still have to tell them how to ask a question properly...
Now, the question was poorly asked (and downvoted and closed), but that doesn't mean that comment is useful or appropriate.
I used to flag these as "Not constructive," which I thought fit them quite well (though as Shadow Wizard points out in a comment, it's a mild description).
I hesitate to flag it as "Rude or abusive" (it's rude; it's not abusive), even though the name says "or abusive," because that seems like overkill.
But "No longer needed" seems like...underkill. :-) (And inaccurate, as has been noted before.)