What a Catholic considers heresy is exactly that: what a* Catholic *considers heresy. The average Protestant isn’t overly concerned about what a Christian from another communion thinks of his or her church… again, a Protestant body might have its own ideas on what actually constitutes heresy. Remember, Luther was excommunicated by somebody who probably had less than pure motives for the excommunication. Luther and his people requested an open council and they never got one. Yeah, Protestantism has as much right to exist as Catholicism or any other Christian body. Again, showing a Protestant a Catholic document showing movements the Catholic Church officially disapproves of means very little to the Protestant. Zealotry ( as I’ve seen here) sometimes relates very strongly to the Truth, sometimes relates hardly at all. The message of Jesus Christ coming to Earth to redeem mankind and establish His Church, which is proclaimed by every Christian body, is indeed a worthy message and those who disseminate it have every right to do so. Rights established, I might add, first by our victory in the Thirty Years War and later by our Protestant forebears who put their ideals of religious freedom into the very Constitution that our country is supposed to go by in the first place.
I don’t think the conversation is about “right to exist” . Anyone can come up with anything and say it is Christian…Westboro baptists?? That doesn’t mean it is Christian.
So the real question is…does someone have the right to create a division in the Church?
1 Corinthians 1:10-13
I appeal to you, brothers, by the name of our Lord Jesus Christ, that all of you agree, and that there be no divisions among you, but that you be united in the same mind and the same judgment. For it has been reported to me by Chloe’s people that there is quarreling among you, my brothers. What I mean is that each one of you says, “I follow Paul,” or “I follow Apollos,” or “I follow Cephas,” or “I follow Christ.” Is Christ divided? Was Paul crucified for you? Or were you baptized in the name of Paul?
Romans 16:17-18
I appeal to you, brothers, to watch out for those who cause divisions and create obstacles contrary to the doctrine that you have been taught; avoid them. For such persons do not serve our Lord Christ, but their own appetites, and by smooth talk and flattery they deceive the hearts of the naive.
Titus 3:9-11
But avoid foolish controversies, genealogies, dissensions, and quarrels about the law, for they are unprofitable and worthless. As for a person who stirs up division, after warning him once and then twice, have nothing more to do with him, knowing that such a person is warped and sinful; he is self-condemned.
Luke 11:17
But he, knowing their thoughts, said to them, “Every kingdom divided against itself is laid waste, and a divided household falls.
Ephesians 4:3-6
Eager to maintain the unity of the Spirit in the bond of peace. There is one body and one Spirit—just as you were called to the one hope that belongs to your call— one Lord, one faith, one baptism, one God and Father of all, who is over all and through all and in all.
“I therefore did what belonged to me, as a man devoted to unity. For where there is division and wrath, God does not dwell. To all them that repent, the Lord grants forgiveness, if they turn in penitence to the unity of God, and to communion with the bishop. I trust [as to you] in the grace of Jesus Christ, who shall free you from every bond. And I exhort you to do nothing out of strife, but according to the doctrine of Christ. When I heard some saying, If I do not find it in the ancient Scriptures, I will not believe the Gospel; on my saying to them, It is written, they answered me, That remains to be proved. But to me Jesus Christ is in the place of all that is ancient: His cross, and death, and resurrection, and the faith which is by Him, are undefiled monuments of antiquity; by which I desire, through your prayers, to be justified.”
-Ignatius of Antioch letter to the Philadelphians
“Do not err, my brethren: if anyone follow a schismatic, he will not inherit the Kingdom of God. If any man walk about with strange doctrine, he cannot lie down with the passion. Take care, then, to use one Eucharist, so that whatever you do, you do according to God: for there is one Flesh of our Lord Jesus Christ, and one cup in the union of His Blood; one altar, as there is one bishop with the presbytery and my fellow servants, the deacons.”
— St. Ignatius Of Antioch, Epistle to the Philadelphians, 3:2-4:1, 110 A.D.
Seems the answer is clear…