It is usually taken that AU/UK have many more words and/or variations which would mean that common speech would have more possibilities to interject a curse word.
I had an American friend at Uni who used to try local swearing or idioms from time to time. "Bloody deadshit!" "Ya reckon?" Relatively tame in the context (bars) he was trialing them. He could never pull it off smoothly, it always got him funny looks. The French, Arab or even Chinese could do it. It sounded fine. Not this guy.
I wonder what makes it like this.
No wonder you ban swearing in The States.
Edit: No malice intended.
They tried a pilot for a localised version once. Never gonna work.
P.S. Actually, I wasn't too sure about Aussie speech patterns besides the usual stereotypes. Either way, with its 22e6 population, it doesn't sway the argument.