One political party in Australia tried to adopt this and starting calling people "un-Australian".

The leader of the other party stood up and tore him to shreds, saying that the magic of Australia is that it's a country of immigrants and that by very definition, everyone there is Australian. It's perfectly fine to disagree about stuff and have discussions, but we're all still Australian. Anyone who says otherwise is trying to tear the country apart and should never be given a microphone again.

The other guy has never tried that childish divisive tactic again.