You are obsessed with this monolithic view of Catholics, which I have demonstrated is incorrect. It is because Catholic is a "universal church" that it is a poor predictive factor.
White Catholic voting has moved consistently to the right for many years, it's an observable trend. Non-Latino Catholics voted 57% for Bush (vs Kerry).
While JFK did champion the immigration reform act of 1965, he'd been dead for almost two years when it passed. LBJ (a Protestant) pushed it through and signed it. A lot of nation-changing legislation was passed in the name of Kennedy: the Great Society and the Civil Rights Act. Conservatives hate most of these, but the GOP were also the leaders in passing a lot of it.
The actual act that became law was introduced by Emanuel Celler, a Jewish Democrat from Brooklyn, in the House, and matching legislation was introduced by Phil Hart, who was an Irish Catholic, in the Senate.
The Senate was strongly controlled by the Democrats at the time, and a majority of them voted for the law. Still the GOP percentage voting for it was even higher!! Wikipedia; "Of the Republicans, 24 voted yes, 3 voted no, and 1 abstained"
The vast majority of Protestants in the Senate (who were in turn the vast majority of the Senate at the time) voted for this bill.
Given this your obsession with blaming the bill on the dead President, Kennedy in particular, or on some sort of Catholic conspiracy, is weird and misguided.
President Lyndon B. Johnson signed the legislation into law, saying "This [old] system violates the basic principle of American democracy, the principle that values and rewards each man on the basis of his merit as a man. It has been un-American in the highest sense, because it has been untrue to the faith that brought thousands to these shores even before we were a country".[10] Hmm, sounds like typical Protestant utopianism was big factor in the passage of this bill. The same people who brought us woman voting and freed slaves, with no sense of the nation as anything other than a "proposition nation" brought the immigration disaster on us out of a sense of fairness.
The heroes in the story were Democrats, specifically those from the South, with their natural conservatism and 'blood and soil' sense of nationalism. Wikipedia, again: " Most of the no votes were from the American South, which was then still strongly Democratic."
A lot of words to say nothing.
States are falling, and the pro-abortion left depends on mass catholic immigration, and we seem to have those who oppose the left’s immigration goals at FR, and those who support it.
The pro-abortion left can only win if we continue to allow this mass immigration, yet Catholics of left and right, seem to support it with single mined passion.