"Anti Catholic tropes" were not the product of 19th century American bigotry. The Papacy was firmly and clearly identified as an antiChristian persecuting power during the Reformation, hundreds of years before. D'Aubigne and Wylie both published extensive Reformation histories in the 19th century. They narrated in shocking detail the campaign Rome carried on against, not only the Word of God but individual rights to believe, think, and express personal matters of faith. In the Netherlands alone, ~50,000 "Protestants" were killed over matters of faith, according to D'Aubigne.
D'Aubigne distinguished Catholicism from popery, believing popery to be the enemy of humanity:
"I think we should carefully
distinguish between Catholicism and Popery. The latter, in my opinion, is an erroneous and destructive
system; but I am far from confounding it with Catholicism. How many worthy men, how many true
Christians, has not the catholic church contained within its bosom! What important services were
rendered by Catholicism to the existing states of Europe, at the moment of their formation — at a
period when it was still deeply impregnated with the Gospel, and when Popery was as yet only
hovering over it like a faint shadow! But we live no longer in those days. Strenuous endeavors are now
making to reunite Catholicism with Popery; and if catholic and Christian truths are put forward, they are
merely to serve as baits to draw us into the nets of the hierarchy. We have nothing, then, to hope for on
that side. Has Popery renounced one of its observances, of its doctrines, or of its assumptions? Will that
religion which was insupportable in former times be less so in ours?"
Preface to History of the Reformation, 1835