Gregory's ServerReally? Given how the content filtering page is currently worded, that implication is a surprise to me. As written, it talks about contexts where copies of a given post do or don't get "hidden". Indeed, the words "as if" imply that the post isn't gone, you just don't see it in (some of) the usual context(s).
Indeed, I deliberately chose to reuse the concept of filtering because email (+ other) filters work exactly the way you want this to.