It is by no means confined to Australia. I have seen it even on this site.
It's a funny thing that people who like to point at Catholics who are democrat have never bothered to look beyond the "social justice" propaganda and see where the problem really started. It wasn't just due to powerful democrat machines in cities, either, or even the appeal to immigrants. Those are popular myths and/or popular democrat propaganda memes, but they're not the heart of the reason why Catholics became mostly democrat.
People in their fifties and sixties these days have grandparents who drummed it into the heads of their children to never trust the Republican party because the Republican party demanded that it be illegal for the Catholic Church to operate schools. The Republican party, in fact, was the driving force behind ending voucher systems and giving state run schools a monopoly on all education. The democrat party promised to keep Catholic schools legal even if the vouchers system went away. They also promised to prosecute people who were part of mobs that burned Catholic properties rather than ignoring it. Given that oft overlooked fact, it's no real wonder Catholics avoided and ignored the Republican party. Nor is it surprising that people who saw Republicans trying to totally outlaw Catholic schools drummed it into the heads of their children to stay away from the party that advocated outlawing Catholic schools. Having parents who made sure they knew that history the WWII generation passed that same outlook along to their children who came of age in the sixties.
People in the sixties generation wanted to be just like the majority in this country who believe in going along to get along and adapted their religion to suit themselves. They left the Catholic Church to embrace contraception, abortion, out of wedlock sex, and a lot of other things the Catholic Church spoke out against but that no one mentioned in non-Catholic denominations. The "social justice" garbage began as a marketing tool to keep the hippie generation interested in the democrat party in spite of the fact that young people were leaving the Catholic Church. People who left the Church eased their guilt at abandoning their Catholic upbringing by lapping up the democrat propaganda lie that supporting a government power grab is the same thing as caring for others. Plenty of weak Catholics, including priests and Bishops, went along with the social justice lies for the same reasons. They wanted to be accepted and also thought latching on to "social justice" would help stop the loss of young people. As willing saps wanting acceptance, they were all easy marks for the manipulators in the democrat party.
There are without a doubt a lot of Catholics who refuse to vote democrat and just don't vote at all. They look at the way the democrat party has become anti-Christ, the constant stream of anti-Catholic slop on many conservative sites, and the fact that even when Catholics do vote for conservatives they're not welcome in most conservative circles, then just stay home. In addition, there are more than a few Catholics who refused to vote Romney just like some Evangelicals did. I've also run into Catholics who say they haven't voted since Reagan because they can no longer stomach the democrat party but aren't welcome in republican circles where they live.
I went to pro-life events starting in the late seventies and it was the late-eighties before I ran into more than occasional non-Catholic at such events. At some of those demonstrations there were people passing out anti-Catholic tracts by "He Who Cannot Be Named" to Catholic pro-life folks rather than pro-life material to passersby. While at that time I wasn't Catholic, I was upset that rather than focusing on the pro-life task at hand some people were so rabidly anti-Catholic that they would rather drive people away from pro-life events than stop spreading lies and beating their propaganda drum for an afternoon. When you really study the situation and look at history rather than thinking the world didn't exist prior to the sixties, there's only one surprise in the voting numbers; the surprising number of Catholics who turned out to vote while so many millions of others stayed home.
Loudmouths who throw Catholics out of the boat and then complain about evil "papists" splashing around in the water are a perfect example of why conservatives come up short in national elections. Whatever those throwing Catholics out of the boat think they're achieving, the only real result of their efforts is to drive people away by reinforcing the democrat propaganda lie that portrays all Conservatives as anti-Catholic bigots. Without a doubt, for every Catholic they drive away they drive away at least one non-Catholic who sees no point in re-fighting sixteenth century Protestant/Catholic religious battles while the nation burns to a crisp. People driven away from the conservative cause more often than not sit out elections, but given the power of Federal vote buying programs, being on the sidelines helps democrat fascists just as much as voting for them.
The majority of non-Catholic Christians on FR are just that, Christians who aren't Catholic Christians, separated brethren but brethren none the less. Those who can't resist attacking fellow conservatives over religious differences may or may not be Christian, but they're definitely ignoring what Christ Himself said on the topic of casting out devils.
Luke 9:49 "And John, answering, said : Master, we saw a certain man casting out devils in thy name, and we forbade him, because he followeth not with us."
Luke 9:50 "And Jesus said to him : Forbid him not ; for he that is not against you, is for you."
Anyone who thinks forcing democrat scum out of office and defeating the democrat fascist machine isn't the same as casting out devils just hasn't been paying attention.