Newly created pages should not automatically appear in the top-level menu of a Commerce site. It should only appear there as a result of a proactive step taken from the backend..
On more than one occasion I've found pages that were either half built or never intended for public consumption directly accessible from the main menu of my site.
This should never be automatic simply because a page was created, and should always require a proactive step before a page shows up on the top level menu of a site.