She has already excommunicated herself.
Nonsense.
As long as the Catholic church continues to treat her as a member, they do not consider her ex-communicated even if you do, except when it's convenient to count her as part of the 1.2 billion strong that Catholics love to brag on.
Besides, that argument is nothing more than an excuse for the RCC not taking action. It does not absolve them of the responsibility they are supposed to take to discipline members who are not living according to Catholic doctrine.
But then, since they can just lazily claim that, they are not forced to clean house by applying the same standards of discipline on themselves, which they would have to do if they started working on the laity.
It's a self-serving, abominable action to avoid having to do the dirty work themselves, and by that, condemn themselves in the process.