Why some menus, even though they are in the “Available” sidebar, do not appear in the specific-role menu?
That’s because the WPAMM uses the highest role to build the list of available menus (usually the admin’s), so you can see al the possibilities.
If a menu item is displayed or not, however, also depends if the user of that role has permissions to access that menu.
For example: Even though the “Slider Revolution” is on the “Available” column, it will only be displayed to a lesser role if your Slider Revolution Settings allow them to access that menu.
The reason why we do that is that WPAMM does not change permissions, so if we displayed this menus, the user would get “No permissions to access this page” errors, making the menu items useless.