At least Hispanic Catholics have the potential to go in a Left direction, and there is a long history in Latin America of them doing just that, especially with the explosion in the great Liberation Theology movement of the last fifty years. The Catholic Church, always a mechanism of stasis and reaction in the reaction in the region, has now also become a nearly revolutionary force since the early 1960’s. Camilo Torres is not some made-up person. He really existed.
The Sandinistas and the FMLN are both Catholics and Leftist. The ELN Colombian guerrillas were always Catholics, and their original leader was a priest with an AK-47. The Chavistas in Venezuela are Leftist and very Catholic.
Believers are now allowed to join the Cuban Communist Party, and there has been a lot of intellectual ferment in recent decades in Cuba around notions of Catholic Communism and the like. Actually there is a long tradition of Catholic Communism predating even Liberation Theology going all the way back to the 1930’s in Eastern Europe. Leftwing Catholics have been arguing that Catholics can be Communists for nearly a century.
How many Protestants do you see making arguments like that? Along with all of the idiocy and reaction of their backwards rules, at least Catholics in general seem to have a much greater tendency to go left, socialist or even Communist, and that tendency seems to be baked right into the religion. The Catholic Worker movement in the US is a good example. How many Protestant movements like the Catholic Worker movement sprung up back then? Basically zero.