I have found that when a chat room becomes "frozen" or "deleted", then if I have starred it I am forced to enter the actual room in order to unstar it as the unstarring option is removed from the SE chat room lists as you can see here:
I assume that this is to prevent people from starring frozen or deleted chat rooms? But the unstar option should not be removed - only the star option if the room is not already starred.
As it becomes rather annoying to have to click at least 3 buttons to unstar a room (and the room may take a while to load depending on how much content it has, so this whole process could take a while) it would be nice just to have the nice and easy option like with the other chat rooms. Especially if you have more than 1 or 2 rooms you would like to unstar.