This is an article about the anti-[Irish] Catholic frenzy in the 19th-century US. Yes, cities that today are as staunchly and archetypically Catholic as Boston and New York, used to be bastions of Protestant whites trying their darnedest to suppress and oppress Catholics in any way, including through physical violence. Anyway, the article discusses a sensationalist book about the bizarre sex and cannibalism rites supposedly going on in convents across the Americas in the early 1800s. It turned out to be a total fabrication, but even after this became clear, people apparently continued to cite the book as a justification for their prejudices.
It all sounds surprisingly close to the anti-Muslim frenzy that prevails in many parts of the US and Europe these days, right down to the specious written reports that people continue to cite even after they've been thoroughly disproven (cf. the alleged Muslim celebrations of September 11th in New Jersey). I am lucky that in my upbringing in modern-day Chicago no one would have thought to question my loyalty to the US, or wondered if I partook in blood sacrifice or incestuous orgies, simply because of my Catholic faith or my European immigrant background. But I can imagine how that would have been for me, and this is a situation that many people of other faiths and backgrounds do deal with in the US today. So this article, along with recent books I've been reading, have given me a bit more direct and visceral empathy for the sufferings of those tarred by their society as undesireables, simply because of how they look or talk or worship.
The Slate article has a great quote to summarize the trends it describes:
"It’s at this juncture that the true purpose of conspiratorial thinking
reveals itself: It’s a way to smuggle a xenophobic agenda into
mainstream politics under the appearance of legitimate fears and