In each case, it was a group of upstarts saying, "We are changing doctrines."
Those who refused to go along were fomenting division. Those who insisted their *new* way of doing things was the only way was the *only* right way were those who liked, um, unity.
Those who didn't go along watched as the "new way" folk gradually maneuvered to positions of power and foisted their new way on the majority. Some just looked and said, "Blessed be the minister who cometh ... um ... in the name of ... whatever." And the majority were like, "They teach. Hey, minister, my mouth is open and I'm on my knees! Teach me!"
Those who were really believers left, reviled for their division-making. *They* were the heretics, as prior church materials were recalled, reinterpreted, and some forgiven after repenting in public for teaching what was suddenly deemed error.
This struck me as stupid. You *change* things and insist others accept, *you* are the one causing division. Or, to use the English word borrowed from the Koine Greek word for "faction", "heresy."
Were I Catholic, I'd have spent the time to learn Latin. (Not Catholic, I still know the proper of the Mass, and have 1.5 years of Latin under my belt). Don't think it's a big deal, which language to use--so when vernacular Mass became a thing I'd have gone to that. But to *ban* the Latin Mass? *That* I don't understand, and that's the heresy. (Yeah, I said the pope was a heretic(k). Then again, I've thought that for a long, long time. They lost me when the 7th day was declared a fast day because, well, Jews observed it, and only Sunday was the proper day of worship. Nicaea? Not a problem. But I have a side in the Quartodeciman controversy, and it's not Pope Frankie's.)
Then again, a lot of this is a proxy war. The Latinate Mass is symbol of those who often uphold old, pre-Vatican II doctrine and traditions against more "modern" doctrine and tradition. Fight the symbol, you fight the underlying reality. Some believe.
I feel sorry for Frankie. He's put in the position of being Pope and upholding Catholic tradition and canon and doctrine, but at the same time his true interests seem to lie entirely elsewhere and he'd like to repurpose the entire enterprise, without diminishing its (presumed) power. But the lure of power and fame ...