Interesting, damn never knew that shyt about JFK. How do Catholics worship Jesus differently from Christians that they got hanged for it?
I don't think it was specifically how they worshiped Jesus more so than it was just general ignorant perceptions of the religion and it's practitioners. I think there were like three factors that contributed to it's perceptions here in the U.S.
First, in the early days, the Puritans, who were escaping religious persecution, originally viewed Roman Catholicism as pagan, which has carried over to become the view of most American born Christian denominations. That's due to veneration of statues, pope, rituals, etc...
Secondly, you got some Church of England influences as well, which viewed "papist" as being the enemies of the monarchy. If you remember, it was King Henry VIII who split from Rome (the English reformation) and started the Church of England where the monarch is the head of the church, because the Pope would not allow him a divorce so that he can produce an heir to the English throne. So right now, Queen Elizabeth II is the head of the Church of England. All royals have to be Anglican and anyone who marries into the royal family has to become Anglican, as Roman Catholics are barred from sitting on the throne of England.
Thirdly, Roman Catholicism's perceptions were shaped by its immigrant practitioners. In the US, that was by the Irish, Italians, and Latins, who in the early history of our country, were not considered "white". They were dirty, uneducated scum who were just a step above Negroes. Those groups transitioned to whiteness in the early part of the 21st century, and with that, you started to see more of an acceptance of Roman Catholicism, culminating with the election of JFK.