It says in the faq:
Why was my feature/bug declined or closed without explanation?
Meta Stack Overflow has been around for a while, and as a result, many issues have been considered in the past. If your feature request has been marked as status-bydesign or status-declined without a comment, it is likely because there is another question that approaches the same topic and a conclusion has been reached. Perhaps you could try searching for your idea with different search terms, hopefully that will find the original discussion.
This should never happen. If a feature request is closed for either of these reasons, there should be an explanation.
Now, if it is closed because it was discussed before, it should be closed as duplicate, and tagged
I think the current version doesn't convey any useful information and is at best misleading. So it should be changed not only in wording but also in meaning or removed altogether.