As an American who was raised Lutheran, who was taught a bunch of Romance-Euro-centric world history in school, I always considered Roman Catholic to be the “default” flavor of Christianity. Protestantism in all of its forms are hard forks. It’s in the name, even–the Roman Catholic church is what Protestants are “protesting”.

To unironically “-and Zoidberg” Catholicism out of Christianity while leaving Protestant flavors included feels completely backwards. I’ve never heard anyone do it.

But if I did, I could only assume it was due to some No True Scotsman bullshit. “Only we practice the correct way. Everyone else isn’t just interpreting it differently, but interpreting it wrong.” Sounds like an Evangelical line of thought to me.