Do Catholics believe Protestants are going to hell?
First of all we have to say it is not our place to judge for God.
Let me also say - “nor is it Protestants place to judge that they are ‘saved’ until God judges them saved.”.
It is never our place to presume to judge for God and to make presumptions that limit both God’s Mercy and God’s Sovereignty.
That said - All Catholics (should) believe the Catholic Teaching at face value. And that is simply that God’s (actual) grace calls every soul to Himself and with consent to that grace can overcome every barrier except an obstinate pride and unrepentant heart. This includes even the stubborn barrier of error arising from non-apostolic Christian (neo-Christianity) teaching. God wills for all to attain to eternal beatitude with Himself. The problem we get into with non-Catholics who call themselves Christian is the assent to a new artificial secular dogma on Justification that irrespective of their formal Protestant teachings pragmatically resolves to something like this for the average man on the street::
*“God knows my heart and my intentions to be a good Christian so whether or not I am in one denomination or another makes no difference since I am a Christian. It’s all the same since “a reasonable God”, a just God and a Merciful God would not hold me accountable for the nit-picky little errors and details of mere human doctrine if my heart and intentions are all in the right place.”
I call this “Pragmatic Protestant “Christian” Doctrine of “Justification” (aka ''God is my buddy and understands and That’s all that matters”)
– Universal Pragmatism).*
The error of course is in assuming that the details of True Apostolic Teaching are unimportant. But this falls apart in the face of the fact that God gave us 31,102 NT verses and 2,000 years of successive and consistent Apostolic Catholic Teaching that has thus far never been able to reduce “salvation” down to a single “one-liner” salvation formulas like “just believe” or “by faith alone”. What we have is a holistic and highly cohesive Catholic Catechism – which all but slays the excuse of ignorance for the vast majority of the educated planet.
From the Catholic perspective we see Protestantism as a single collective error with many facets that is internally fractured through the core error of insubordination to God’s Ecclesial Authority. While it is VERY true that Christ’s resurrection reconfigured all Creation towards God the clear error of Protestantism’s muti-denominational effect goes contrary to that central gravity in its “collective” assumption that entry into beatitude is by way of a wide gate or multiple narrow gates. From any single denominational perspective it appears “narrow” but from a universal, Catholic, view it’s clearly unlike what Jesus describes by the “narrow gate” description.
In the Catholic view, God’s people are ordered (and counted and inspected - one by one). We know that what belongs to Jesus can only pass through the narrow standard one-by-one as if by single orderly file in order to pass through. And that means all following one behind the other – with all behind the shepherd and all in one single line. The shepherd is real and visible and it is Peter’s successors - NOT the hired hands who preach for hire. Nor will Jesus take the sheep together with the goats who try to cut in from other lines from foreign flocks. Only those who are in perfect holiness will go through the gate and enter into eternal beatitude. Further, beatitude it’s not as much a matter of numbers as it is a matter of quality. Protestantism’s aversion for not boasting by works has made it easy to completely ignore the necessity for Holiness and the mandate to “…be perfect, as your heavenly Father is perfect. (Matthew 5:48).” That requires regular routine disciplines of bathing (confession) and shearing (penance) and health checks and eating of good food (Eucharist) and exercise (prayer).
What matters here is if one cooperates to “hear” that universal call or if one is too preoccupied with one’s own self-centeredness or human-condition to respond to that call. What is clear is that a “right relationship” with God (aka Justification) is absolutely essential in order for sanctifying grace to take residence in an individual and that grace to work (not the old sinner) to make them Holy. It is thus very very possible for many non-Catholics to attain to an initial Justification through faith in Jesus and being baptized (either by water, blood or by desire) become holy. But what is VERY difficult for those outside the formal Church is for souls to remain in a state of justification and holiness such that they actually may progress through the complete sanctification process to become Holy and stay such; all way through the narrow gate to the very end of mortal life. Sanctification is not complete until the soul’s sanctification is tested in the judgment that occurs in the transition from mortal life to physical death to eternal life). The Catholic Church, as Christ’s Body, has as if by divine arteries, enormous channels of grace available to it directly from the Divine Heart of Mercy through the seven sacraments (esp. Sacraments of Penance and Eucharist) to bring us channels of massive grace to help us stay in holiness. Catholics are collectively in wildly different levels of personal sanctification. But the sacraments keep everyone who avails them in grace and holy before God so if they are called home at any moment they have confidence they are in a state of eternal sanctifying grace (which may require imperfectly repentant souls to spend some additional time in purgatory for final polishing).