As I understanding, flagging brings articles to the attention of the secret cabal of editors (no one knows who they are, beyond the fact that pg is likely one of them). The more an article is flagged, I presume, the more it stands out to their attention. They then make a manual decision whether to kill the article - and can even bring it back if they change their mind (I've seen that happen a few times).
So flagging in and of itself does not trigger any automatic removal of the article. There has to be a human action to remove the offending article.