Some Protestants hold to more errors than others, and some ally themselves in modern times with evil forces to spread wickedness in our culture, while others fight these people in order to spread righteousness.
I think we basically have to support all that is good and resist all that is evil. So we need to ally with and encourage Protestants in the good they are doing while working to dispel the errors they hold to. We need to do all things in love, and when we can’t, we need to pray to be able to.
For a time, I hated Martin Luther. I seriously hated him because of how he tore apart the Body of Christ, encouraged bigamy, tried to get “Papists” killed, encouraged and then ruthlessly betrayed the German Peasants’ Revolt, spread abominable doctrines, sought the destruction of the Jews and everyone who disagreed with him, and encouraged the spread of many sins. I read from his books and they were abominable.
However, I felt the Lord calling my spirit toward forgiveness and when I told my priest in Confession about my hate, he told me to pray for Martin Luther’s soul. So that’s what I’ve been doing. It’s extremely hard, but it helps to dispel some of that anger.
That man was evil, like Hitler was (and indeed, Hitler was largely following his teachings), but it would be hard to find any modern Protestants like him. Conservative Protestantism today is very different from 16th century Protestantism, is a lot more open to truth and less violent in error. Most conservative Protestants are holding fast to Christ insofar as they are able. I lived among them and know what they are like and believe, and there is a LOT of holiness among many of them. Many are sincerely following Christ insofar as they are able, given what they have. They are a great, great blessing to our modern society, certainly part of the “salt of the earth” that brings delight to God and is a stench in the nostrils of the wicked men of the world.
Would you join me in praying to Mary for all the Protestants? Many of them are our natural allies and we need unity with them, for they are part of the Body of Christ and Jesus calls on all His Body to come to Heaven perfectly, as one (John 17:23). You can’t imagine how blessed we would be to have them as our companions in fighting the world’s evil, whether in full unity or not!