The Culdees is it, then? Father Knox is doing 500 RPM in his grave under the cold peat.
I was asked a question that seemed to beg an opinion. I attempted to summarize long events into an understandable digest that takes rather longer to get a good grip on - not for complexity; but, for volume. But, I'm sure that Rome exterminating folks they didn't want to hear from "in the name of Christ" played a huge role in getting Catholicism extricated from the Britains.. which seems to be your main questions. Knox didn't shy from the sword. Perhaps he should have; but, he fed you like for like which you find injurious.
Do tell.