I was almost afraid to find out, half expecting to find some particular group that the author had an axe to grind with. His "modern parallels" actually span many groups over several centuries. I do not know enough about the Donatists or the other groups to say if there is indeed a parallel or not. Interesting article, though.
Curious as to why you refrained from the last two paragraphs.
The reference to traditionalist groups. We do enough squabbling under our own steam on FR and it seemed like a little extra fuel. Sometimes we get just a hair over the top in our comments to each other. Especially when we start implying the other person is a 'traditore' or traitor to the True Faith.