Jon, ask your priest.  I'm not chastising you, I'm not Catholic.  You might be surprised to know there's only one Pope in your organization, he doesn't claim as much or frequent infallibility as you do.  I think if you consult your (not my) catechism you would see that if (rare cases) a person were excommunicated it is an act of charity.  It means the Church sincerely believes that receiving communion would actually be harmful to the person.  It isn't "seen" normally because it's infrequent and a pastoral issue between the layman and their priest who *is* responsible for he communes or does not.  Both grave responsibilities.   Nobody wants to get "between" you and God.  Nobody can.