There is a difference there even if no one wants to admit it. The difference is between one who was never Catholic having to go through at least a few months to a year of instruction and THEN become a member of the Church before finally being absolved in confession, and a Catholic who has to make an abjuration of heresy, even if that's before the whole world, and then be absolved in confession.
Yes, the difference between Martin Luther (a catholic) and a guy like Charlie Kirk (protestant). Yes, it's a big difference. Your point is well taken.
Fr. Luther only had to abjure his heresies to be absolved - yet, he remained a Catholic priest in the sin of heresy through it all. And yet the no good heretic could still do what all Catholic priests do, namely, administer the sacraments in dire emergencies. Since his death, it is to his everlasting shame that he will always be a Catholic priest for all eternity. The evil excommunicated heretic, apostate and schismatic that he was, he never ceased being a Catholic priest.
Yes, we get your point. He's still a priest.
But your ignoring the other problem. Luther was excommunicated, just like all modern-day Modernists. Masons, heretics, etc are in a state of MAJOR excommunication (and all manner of canon law penalties). These CANNOT be removed simply by confession.
There's a process; a public meeting; a trial. (assuming the Church was operating at full, anti-heretical capacity). So a 'public, manifest heretic' can be forgiven ONLY AFTER they abjure their heresy.
It's like a thief who stole $100,000. Can they simply go to confession? No. They must also do restitution and pay the money back.
Can an excommunicated heretic simply go to confession? No. They must make PUBLIC restitution and PUBLIC abjuration of heresies, towards the public, whom they scandalized and led into sin.
Do you get the point?