Because they are liberal, and have always been, just like the majority of Catholics, post 8 did not make Catholics vote for Obama, they do it because they are Catholic.
Prominent Democrats the party of the KKK, write all the anti-Christian books, make the movies, run the anti-Christian news shows, TV shows, comedy acts, newspapers, magazines, etc, etc, and you think that the reason Catholics vote Democrat is because they saw post 8, or heard a rare anti-Catholic remark somewhere that didn't come from a liberal?