Australia is a nation of immigrants. As the joke goes, Australia's forefathers were selected by the best British judges. Australia, unlike America, was a penal colony. Many settled here rather than go back to the UK. Many were Irish, not exactly best mates with the British establishment.
After WW2, a lot of Greeks and Italians settled here. Many New Zealanders also. At one time Sydney's Kiwi population was more than the second largest city in NZ. After the Vietnam war finished, a great many Vietnamese, mostly ethnic Chinese came here. They added to the Chinese who came to work in the goldfields in the late 19th century. There were Afghan camel herders as well.
Now it is people from India who make the majority of migrants. We have a refugee program so there are also Sudanese, people from Kosovo, Russia, Ukraine, Lebanon and a number of other nations. A bit over a quarter of Australia's population was born overseas.
We have our share of problems. There are ethnically based organised crime gangs. The Mafia set up shop here, Chinese Tongs and Middle Eastern crime gangs. Of course they mostly deal in drugs, but stolen cars are big business as well. However, compared to most countries we're pretty well off. I've travelled a bit, including twice to America. I lived in NZ for a couple of years. I was born in England. Australia suits me just fine.
I don't see that arming the population is going to help if a government decides to crack down. Even an Armalite is useless against an armoured car. And if people decide to take sides. all you have is the potential for a bloody civil war.
Yes.... Australia IS a nation of immigrants, much like the US was.... except, as you noted, Australia was a penal colony...
I would hazard a guess that y'all's crime rate was really not all that bad, until the flood of immigrants that were not anywhere near like the "normalized" Australian citizen.... because as you know, all those immigrants that came to Australia at the start, BECAME Australians.... they were a nation.... made up of different folks whose sum was greater than the individuals.
Now, introduce totally different immigrants..... folks that do not have the desire to become "Australian" ..... and your crime increase happens.
Similar things are happening in the US, but we
started out with an ethnic group that, for the larger part, were not allowed to become part of the American culture. After some years of not being allowed to, they have decided they don't WANT to be a part of it. (remember, I am speaking in generalities.... certainly not ALL members of this ethnicity feel that way)
This is where a very large part of our criminal element originates.
Add to that the influx of literally millions of a different ethnicity, of whom many only want to be given free stuff, and have no desire to assimilate into the culture of the US, along with a large percentage who are simply criminals looking for greener pastures.. and you have added a whole new element of crime....