Why wait? If Automatic Excommunication (AE) is being doled out for abortion because abortion is murder, then I really don't understand why AE isn't given for murder. For that matter, why isn't it given for any other sin?
If sins are things that God hates, and there are some sins that he hates a lot, then why not give AE for all of them? Why not remove the guesswork, the soul-searching, the different rulings from different officials and streamline the whole thing? Do a sin = AE, end of story.
Saying that abortion merits AE because it's murder, but murder doesn't, just shows how wacky the Church is.