On the contrary, it makes perfect sense. Any Catholic who votes like a Catholic will vote pro-life and pro-family. If your "conservatism" is pro-life and pro-family, that's what they'll vote for. If it isn't, it's not worth fighting for.
As far as Catholics who don't vote their faith, if their Catholicism is left behind when they go into the voting booth, what's the point of calling it the "Catholic vote"? You might as well call it the "functional-atheists-who-self-identify-as-Catholic" vote, because that's what it is.
I guess being baptised and being Catholic doesn’t count unless one votes as you do, that doesn’t really work in voting demographics discussions.
It sure doesn’t help on this thread where we are discussing Catholics moving to the South, we have to assume that they will vote as Catholics always have in America.