No. The "Catholics" did not perp the JFKA. But this is an exercise to show how biases and facts can lead to JFKA narratives.
How to Construct a JFK Narrative or Hypothesis: Example
1. The Kennedy Administration had the Catholic Diem brothers, then leaders of South Vietnam, assassinated on Nov. 2, 1963. Some, such as President Lyndon Johnson, would say President JFK authorized the assassination. Indeed, an overlooked document first released in the Pentagon Papers, now known as Cable 74228, shows JFK gave SV plotter Big Minh "a green light and instructed American officials in Saigon not to take a position on any of the coup plans," which was tantamount to approving of Big Minh's coup. https://prde.upress.virginia.edu/content/JFK_Vietnam2
President Nixon also suspected the Kennedy Administration essentially had the Diems assassinated.
2 JFK, a Catholic, was assassinated on Nov. 22, less than three weeks after the Diem assassinations. Madame Nhu, sister in law of the murdered SV president, had all but vowed revenge. President LBJ told CIA Director Helms he thought the two assassinations were related. President Nixon also thought the assassinations were connected.
3. The head of the CIA in 1963, an organization many suspect helped perp the JFKA, was run by a Catholic, John McCone. After the JFKA, McCone was the first non-family member RFK met. McCone appeared to act as RFK's "handler." But McCone was no ordinary lay Catholic. In 1955 Pope Pius XII made McCone a Knight of St. Gregory, and in 1956 the Pope awarded McCone the Grand Cross of the Order of St Sylvester--in layman's terms, McCone was a "Knight of Malta."
As a Knight of Malta, McCone joined the Catholic elite in the Vatican annually on St. John’s Day. Dressed in scarlet uniforms and black capes, brandishing swords and waving flags emblazoned with the eight-pointed Maltese cross, these Catholic brothers will, in an atmosphere of pomp and circumstance befitting a coronation, swear allegiance to the defense of the Holy Mother Church.
4. The South Vietnamese Catholics were very tight with Gen. Edward Lansdale, who many suspect was in Dealey Plaza on Nov. 22. The SV Catholics had voiced strenuous and bitter resentments to Lansdale, regarding the JFK Administration assassination of the Diems. Lansdale was intensely angered at the Diem murders. Lansdale was a Catholic too, and a close personal friend of Madame Nhu and the Diems.
5. Jean Souetre (he also used the names Michel Mertz and Michel Roux) was a member of the French Secret Army Organization (OAS). Many suspect Soutre, a Catholic, was the gunman in the JFKA. France is, of course, a Catholic nation, and much more so in the 1960s. Souetre is known to have been in Dallas on 11/22.
6. The OAS, largely composed of Catholics, tried to assassinate de Gaulle many times. They were an organization with the skill set to perp an assassination. They had means, motivation and opportunity.
7. JFK had supported the Algerians in their bid to de-colonize. The OAS was staunchly against Algerian independence, which would inevitably lead to Muslim rule, and had very strong motivations to perp the JFKA.
8. The largest religion in Cuba, and among Cuban-Americans and exiles, is Catholicism. Many suspect the Cuban exiles, who were largely Catholic, also helped perp the JFKA.
9. The Vatican in Rome can claim 1.4 billion adherents, with organizations and networks in every continent. The wealth concentrated in Rome is incalculable. The Opus Dei arm of the Vatican is considered very right-wing. (By comparison, there are 16 million Jews in the world, and that may be a generous count.) The Vatican in the 1960s worked closely with the CIA wherever there were Catholics, that is, in Eastern Europe, Italy, Latin America and South Vietnam.
10. LHO's relatives in New Orleans, and whom he lived with a while, were the Murrets, a Catholic family with ties to area Catholic/Italian mobsters.
11. Jack Ruby, although Jewish, was "mobbed up" and answered directly to his Italian-Catholic bosses, including the Civello and Campisi families. Ruby gunned down LHO on orders from the Italian-Catholic mob. The first visitors to Ruby in jail after the LHOA were the Catholic Civello and Campisi families. Ruby was a pawn.
12. Miami and New Orleans, which apparently birthed so many elements of the JFKA, have large Catholic populations, due to French-American, Cuban, Latin American and other residents. There are extensive Catholic networks of religious, charitable, and political organizations in both cities that can be utilized to launder money and transport goods and people.
13. Keep in mind: On July 27, 1963, less than four months before the JFKA, Oswald was summoned to deliver a lecture to a group of Jesuits in Mobile, Alabama, at their House of Studies--and LHO went there. Jesuits are the on-the-ground shock troops of the Rome-based Catholic empire, the men who converted much of the New World to Catholicism---including the Cubans. It is possible the Jesuits summoned LHO to evaluate him for a role in the pending JFKA.
14. On the seven-man Warren Commission sat John J. McCloy, and Hale Boggs, the latter a "practicing Roman Catholic."
15. E Howard Hunt, who wrote of his involvement in the JFKA, was a Catholic.
16. The largest landowner in SV, before the communists took over, was the Catholic Church. They had a tremendous stake in returning Catholics to power in SV, and also in saving Catholics from communist rule.
17. Johnny Roselli, a Mafioso connected the JFKA, was Catholic, and Robert Maheu was a graduate of Holy Cross College. It was Maheu who connected CIA Catholics to Roselli and Mob Catholics.
18. The Vatican gave the "Sovereign Military Order of Malta" award to James Jesus Angleton---for his work in helping to bring about the JFKA? Angleton's mother was a Catholic.
19. On Sept. 7 1963, the Catholic Fidel Castro said this: “If U.S. leaders are aiding terrorist plans to eliminate Cuban leaders, they themselves will not be safe. Let Kennedy and his brother Robert take care of themselves, since they too can be the victims of an attempt which will cause their death.”
Conclusion: There is hardly any aspect of the JFKA that is not infused, suffused and refused with Catholic participants.
It is possible the JFKA was a Catholic cabal "revenge killing" for the Diem assassinations, mixed in with other secular motivations such as those at the CIA, or the Catholic-dominated Mob, Cuban exiles, and OAS militants.
Even the CIA was led by the Catholic John McCone, on Nov. 22, 1963.
Tell Jeff Morley to start dog-whistling "the Vatican was involved in the JFKA."