You might want to check your own Church’s writing on this. Even the Catholic Church doesn’t regard Protestantism as heresy. By definition a heretic cannot go to heaven and the Catholic Church has stated several times that they do not believe that only Catholics go to heaven.
That’s why I took care to separate Protestantism from individuals in Protestantism.
Here is an excerpt from the
Catholic Encyclopedia:
St. Thomas (II-II:11:1) defines heresy: “a species of infidelity in men who, having professed the faith of Christ, corrupt its dogmas”… The subject-matter of both faith and heresy is, therefore, the deposit of the faith, that is, the sum total of truths revealed in Scripture and Tradition as proposed to our belief by the Church. The believer accepts the whole deposit as proposed by the Church; the heretic accepts only such parts of it as commend themselves to his own approval. The heretical tenets may be ignorance of the true creed, erroneous judgment, imperfect apprehension and comprehension of dogmas: in none of these does the will play an appreciable part, wherefore one of the necessary conditions of sinfulness–free choice–is wanting and such heresy is merely objective, or material.
newadvent.org/cathen/07256b.htm
As for individuals of good will who are Protestants:
With regard to persons born in Protestant countries and validly baptised, who, from want of instruction and opportunity, have never come to the knowledge that the Catholic Church is the only true Church of Christ, if they have never committed a mortal sin, or have atoned for their sins by perfect contrition, united to a sincere desire of doing all that God may require of them, they will be saved in the ordinary way, as members of the Catholic Church. Such persons are in reality Catholics; they have entered the Church by valid baptism, and are only outwardly separated from her communion by inculpable error.
From
Protestantism & Infidelity by Father Wininger (available on Google Books)
So, yes, Protestantism is heresy, but Protestants (those validly baptized) who are of good will are, in reality, Catholics.
Also Most High Litergical Church’s Baptism’s. Marriages etc. ARE recognized by the Catholic Church. As a Lutheran MS I would not even have to go through the entire RCIA process to convert if I wanted to. Lutheran’s actually do hold confession as a sacrament, per the small catachism. It just doesn’t have to be done one on one with clergy, but it is performed at every service BEFORE recieveing the Body and Blood of our Lord. We also regard Holy Communion as a sacrament, the arguement between the Catholic and other High Litergical Churchs on Communion is really spliting hair in my book. Also the High Litergical Churches also practice confirmation they just regard it as an extension and completion of the Sacrament of Baptism. Also if ABC is all that is needed to break the sacrament of Marriage…well people in glass houses…Many Catholics I know practice ABC right or wrong too. It might interest you to know that more and more protestants are actually turning to NFP as it is way healthier for women than the pill.
My personal knowledge of Protestantism comes from Evangelical Protestantism. I try to differentiate, but sometimes I get careless.
If you want to promote Christian Unity, as Pope Benedict has been trying to do…you might want to stop calling other Chritians names and being uninformed and rude about their doctrine. Also the OP asked for a discussion on the differences not a “Catholics are the best and everyone else sucks thread”.
I’m not trying to be rude, I’m simply using Catholic terms in their proper sense. I do admit that my experience with Protestantism comes from “Evangelical” Protestantism, but all Protestantism
is heresy – at least objectively. It chooses what part of the True Church’s teaching to accept and what part to reject.
What is your definition of “heresy?”
As to your statement about the “Pillar of Truth”…even the Catholic Church has admitted it is not the “Fullness of Truth” as all Turth has not yet been revealed to us men. Also to expect another denomination to say that the Catholic Church is the “Pillar of Truth” is silly. Obviously if we believed that we would be Catholic

. That statement is as silly as Muslims getting mad when Pope Benedict said that Christianity was the One True Faith…come on if he thought that Buddism was the one true faith he most certainly is in the wrong job.
I’m sorry, but I happen to disagree with Modernists, as described by St. Pius X. I’m afraid many Catholic writers, including those with high positions in the Church, are now Modernists, and in error. Since their writings oppose “ex cathedra” pronouncements I can choose to believe the earlier
authoritative documents.