Again, the whole point is that "excommunication" does not mean expulsion from the Church.
Says you. According to St. Robert Bellarine, excommunication severs from membership in the Church.
In any case, there' a Venn diagram overlap between excommunication and heresy/schism, as one can be excommunicated for reasons other than heresy/schism (e.g. gravely immoral activities).
As I've pointed out before, you're seriously lacking in basic logic skills. Someone who remains in a state of heresy/schism cannot be forgiven the Sacrament of Confession. According to your absurd reasoning, someone who was baptized Catholic but then by the age of reason was being raised as, say, a schismatic or Protestant, can just go to Confession to a priest and be absolved ... without first having returned to a public profession of the faith (i.e. to Catholicism). If the individual is eligible to go to Confession and be absolved, it's predicated upon the idea that he's repented of his heresy/schism first and has returned to membership in the Church. Absent that condition, he may most certainly NOT just be forgiven in Confession, nor is a priest permitted to absolve such an individual (it would be a sacrilege). If his rupture with the Church were notorious, he's have to first make a public abjuration (except in danger of death). Otherwise, simply resuming the profession of the Catholic Church as the true Church and rejecting the profession of heresy suffices to re-establish membership in the Church based upon the criteria set out by St. Robert Bellarmine.
Can an individual who was baptized Catholic, but then at some point became a schismatic or heretic (e.g. Protestant) simply go to Confession and have his sins forgiven? Would a priest be allowed to absolve such an individual? Of course not. Why? Because he's no longer a Catholic. Now, as soon as he renounces his heresy and/or schism (provided there's no other obstacle remaining), then AT THAT TIME he'd be able to go to Confession.
You get hung up on these mental obsessions and stupidities.
Unfortunately, Stubborn, you are a heretic and schismatic ... having professed an ecclesiology that is 100% Old Catholic.