Interesting. The Religion Forum has a few "I used to be Catholic till I saw the light" posters on it, I'm not surprised to hear that according to your quote, they're liberals.
“* Ex-Catholics. Solid for the Democrats. Cultural conservatives have no chance.”
That would not include the Catholics that move to more conservative christian churches.
“Latino Catholics and those without religion are most likely to prefer the Democratic Party, while the non-Catholic [Hispanic] Christians prefer the Republican Party.
“Whereas Latino immigrants are contributing significantly to the stability of American Catholicism, the younger generation and the U.S.-born population are tending to polarize between those moving away from religion and those moving towards conservative Christian traditions,” summarized Trinity professor Barry A. Kosmin”