Err... I'm from Australia, let me share a little of my knowledge.
Border security may seem racist/sexist, but it is usually about certain things i.e. baggy clothing can hide drugs and weapons, people who are strung out tend not to be clean shaven etc. So yes it is profiling, but it's not necessarily motivated by race. With that said, some of them are idiots, sorry bout that.
People here tend to use racial taunts and sometimes just swearing as a form of hazing whoever they talk to. For example, earlier in the week there was a topic about the C-word, here there are two contexts for it and you can tell by the manner in which it is delivered: "Yo C-word" is a greeting, where as "You are a C-word" is offensive.
My best mates include people from different races, so we refer to each other as black, white and yellow all the time. Combined with the above method of swearing in normal conversation to outsiders it does seem really offensive, but it's just friendly banter.
So on the outside I think Australians get a bad rep, but when it counts we'll always help out someone no matter who they are... Though I was bashed because a Muslim woman had "fallen" down some escalators and I helped her to get up, there was a large group of Lebanese men standing around not helping her that then followed me to the car park. It's not the only time, and is apparently against most middle eastern cultures to touch or talk to their women.
So maybe... it's just certain cultural values that conflict with Australian values that create a feeling of racism... anyway back on topic.
As a regular Australian. I've never heard gunfire, or seen a real gun that wasn't carried by a police officer. As for robberies with melee weapons such as knives, it is much easier to run away screaming for help. I remember the news around the time of the Port Arthur Massacre, and the strict gun laws have made everyone feel safer.
Now let me tell you about all those people who are like, criminals will always have access to weapons. Guns, being much harder to get do have a black market even here. This appears to be primarily controlled via bikie gangs. However, bikies and upper level criminal organisations have structure as well. This means that aside from bank tellers and gas station owners, few other members of the law abiding public will have guns waved at them. Police and other bikies appear to be the individuals most at risk. Mass shootings appear to be a concern of theirs and anyone of their own displaying mental health defects are neutralized (More for the safety of other members, but it provides a mental health checks as a secondary effect).
Someone outside of said organisations is going to have a hard time acquiring a weapon from them, let alone enough ammunition to be able to do anything on a large scale. Not to mention that the cost of illegal automatic weapons would be sky high due to their illegality.