How do you remove submenu pages
Reading the WordPress Codex for remove_submenu_page only helps a little with this. The problem is that our joining ampersand, the "&", is entified. Therefore, you need to write the second argument of the `remove_submenu_page` call using `&`.
See Gist "Remove custom post type submenu pages" for examples.
Thank you to bullseyedesigns for suggesting this.