The SSPV, The Roman Catholic,  Fall 2003, p. 7: “With the strict, literal interpretation of this doctrine, however, I must take issue, for if I read and understand the strict interpreters correctly, nowhere is allowance made for invincible ignorance, conscience, or good faith on the part of those who are not actual or formal members of the Church at the moment of death.  It is inconceivable to me that, of all the billions of non-Catholics who have died in the past nineteen and one-half centuries, none of them were in good faith in this matter and, if they were, I simply refuse to believe that hell is their eternal destiny.”

Did you mean to post the following?

http://www.newadvent.org/fathers/1102043.htm


Chapter 1
1. The Apostle Paul has said: A man that is an heretic after the first and second admonition reject, knowing that he that is such is subverted and sins, being condemned of himself. Titus 3:10-11 But though the doctrine which men hold be false and perverse, if they do not maintain it with passionate obstinacy, especially when they have not devised it by the rashness of their own presumption, but have accepted it from parents who had been misguided and had fallen into error, and if they are with anxiety seeking the truth, and are prepared to be set right when they have found it, such men are not to be counted heretics. Were it not that I believe you to be such, perhaps I would not write to you. And yet even in the case of a heretic, however puffed up with odious conceit, and insane through the obstinacy of his wicked resistance to truth, although we warn others to avoid him, so that he may not deceive the weak and inexperienced, we do not refuse to strive by every means in our power for his correction. On this ground I wrote even to some of the chief of the Donatists, not indeed letters of communion, which on account of their perversity they have long ceased to receive from the undivided Catholic Church which is spread throughout the world, but letters of a private kind, such as we may send even to pagans. These letters, however, though they have sometimes read them, they have not been willing, or perhaps it is more probable, have not been able, to answer. In these cases, it seems to me that I have discharged the obligation laid on me by that love which the Holy Spirit teaches us to render, not only to our own, but to all, saying by the apostle: The Lord make you to increase and abound in love one toward another, and toward all men. 1 Thessalonians 3:12 In another place we are warned that those who are of a different opinion from us must be corrected with meekness, if God perhaps will give them repentance to the acknowledging of the truth, and that they may recover themselves out of the snare of the devil, who are taken captive by him at his will. 2 Timothy 2:25-26
2. I have said these things by way of preface, lest any one should think, because you are not of our communion, that I have been influenced by forwardness rather than consideration in sending this letter, and in desiring thus to confer with you regarding the welfare of the soul; though I believe that, if I were writing to you about an affair of property, or the settlement of some dispute about money, no one would find fault with me. So precious is this world in the esteem of men, and so small is the value which they set upon themselves! This letter, therefore, shall be a witness in my vindication at the bar of God, who knows the spirit in which I write, and who has said: Blessed are the peacemakers: for they shall be called the sons of God. Matthew 5:9

Obstinately denying any of the above is damnable.  Since we can't know for sure that someone is in good faith, we should pray for the salvation of all Protestants, and assume that they are not safe where they are.