The K of C started out as a mutual benefit society to provide life insurance to Catholic working men. Most of the other societies that did that sort of thing in the 19th Century either discriminated against Catholics, or were organizations (like the Odd Fellows and Freemasons) which Catholics were prohibited from joining.
Interesting that Freemason's wouldn't let Catholics join. Because as late as the early 60s (and perhaps later), a significant portion of Southern Baptists intensely distrusted both Freemasons *AND* Catholics, imagining conspiracies everywhere (hence JFK's address to a S. Baptist conclave to assure them that he wouldn't be taking marching orders from the Pope).
Of course, some Baptist denominations (especially the ones who claim they are NOT a denomination) have been wont to even attack other Baptist denominations.
Pre Civil War, there were entire political parties dedicated to one single issue of opposing some group or other. Eg the Know-Nothing Party (anti-Catholic), and the AntiMasonic Party.