The standard login window appears, if the Website-App is not yet active and looks like a normal Login-Page to a private space.

After activation of the Website-App the same URL used before for login points to an unconfigured website with links to News & Availability and is listed by Search Engines, even if no site is currently in status "published". 
So before we're configuring the websites layout, it's already published for target group customers, promoting a bad reputation for the businesses using Odoo. 
Additionally, News/Blogs can't even be deactivated/unpublished... 

Imho this should be a priority to get fixed.

Not sure what you call standard login window. Can you share more details about the issue you are encountering?