As mentioned in GTNPORTAL-2033/
JBEPP-1096, "Visible" and "Publication date" are effective only for Navigation. Pages are still accessible via direct URL access, such as http://localhost:8080/portal/private/classic/pagename
This JIRA is raised for a feature request to implement the function to completely hide a page from users. It may be going to add some capability to "Visible" and "Publication date" feature.