It does not do that. Adding ?status=something to the URL simply changes the topics displayed to you. Removing it (or navigating around the site) will reset the view to default. In the case of ?status=open it will remove any closed topic from the current view, allowing you to see only open topics. Other useful statuses are ?status=closed, ?status=unlisted, and ?status=deleted, keeping in mind the latter two only work for site staff.
Try adding ?status=open to the URL of Meta. Notice that the pinned welcome topic no longer appears. If the pinned topic is already not at the top, try going to Contribute > Bug, switching to the latest view, and adding it there. You should notice that all closed topics disappear.