I'm not shure if this is a bug or a feature... If I disable a site-structure's frontend menu status and enable sitemap, it's nor visible in the menu (good!) neither in the sitemap (although activated!)...
You might comment, that disableing the fronent menu status means disableing the structure completely on the frontend, but if there are two values for menu and sitemap I'd consider them to work autonomous...
Bug or feature?

Best regards... Andreas