Not sure a religion that is anti gays and against abortion could be seen as liberal. Hence probably why the publisher believes that those that still practice their faith as catholic maybe conservative.
Also If that's the case based on my choices on the link
@RAFUH posted it should have given me Democrat first before i changed it to Atheist. Given that like she points out that the page notes that religion is the strongest predictor.
I would bet if we were to look at the stats of Catholics voting for Democrats or Republicans it would be the later. I do remember reading that Obama was given more votes by Catholics and it was a surprising shift because before him Reagan and both Bushes got more votes as did the Republican candidate against Clinton. Although Clinton got more than previous Democrats.
Obviously with the growth of Latin Catholics that would probably shift given how they normally vote but even then not by much.
I also googled the Catholic vote in the last election and 52% of Catholics voted for Trump and Pence.