False. The truth is that a bare majority of Catholics -- the same percentage as the rest of the population -- voted for Obama.
As for why they did that, you can only guess.
If you restrict the selection set to only those Catholics who actually attend Mass weekly (meaning that they are at least somewhat obedient to the requirements of their faith), you have about a 4-percentage point win for McCain-Palin.
If you read the article you’ll see that it discusses these facts.