@Tom.Fox, The current web planner is designed around the routing engine itself. Therefore some options are only available from within an open route. You do not need to create a new route to delete favorites, just open any route from your library (but not a track).
A completely new web planner platform is on the verge, you will most likely have seen that in your mailbox. In it things like favorites and POI have their own place in the main menu, and management of them has been greatly improved.