Ahhh I think a bit of research on John Kerry’s self-excommunication also applies here.
Excommunication is a specific penalty in the Church’s law. Some actions do result in automatic excommunication.
Promoting abortion is a mortal sin. One who promotes abortion is not in union with the Catholic Church. But he does not incur an automatic excommunication.
Pro-abortion people must not approach for Communion. Publicly pro-abortion people must be DENIED Communion. But the Denial of Communion is not excommunication, and not a penalty at all. It is a demand of the moral law, and required by Canon law—Canon 915.