He was, after all, of sound Anglo-Saxon stock. At least since the Irish settled down, such people are not terrorists, even if they are burning down abortion clinics or beating up minority groups. It appears that Harper-Mercer had developed some sort of animus against the Christian religion, and asked most of his victims to identify their religion before he shot them, though it does not appear that he spared those of particular religions, or none. But no one spoke of religiously motivated violence.

Though he had the usual arsenal of weapons one might expect in everyday American mass murder, he was not, in having them, breaking the law. Rather he was exercising his right, (perhaps, according to some Republicans his duty) to bear arms under the Second Amendment to the US constitution.

It seems that his major grievance against the world was that he did not have, and never had had a girlfriend, or really, any friends at all. He feared he would die friendless and a virgin. None of his classmates seem to have responded positively to such overtures as he had made.

He had also noticed that people who were nobodies tended to become somebodies – getting themselves profiled in The New York Times for example – if they engaged in mass shootings. That profile says, for example, that a blog on his website expressed sympathy for a dismissed television reporter who recently killed two former colleagues in mid-broadcast: "I have noticed that people like him are all alone and unknown, yet when they spill a little blood, the whole world knows who they are. Seems the more people you kill, the more you are in the limelight."

Now the awkward 26-year-old loner is famous too. There are those in the US, mostly of the gun-toting right, who would rather that we, the gutter press, never ever mention his name, thus denying such losers, of whom the US seems to have so many, the limelight many are thought to crave. Discussion of this interesting theory (which might be right) also helps distract the debate away from the nagging question of how easy access to rifles, pistols, grenades, explosives and assault weapons heightens the American propensity for mass murder. And to reinforce the theory that the registration problem for the authorities is of identifying and incapacitating all non-white and non-Protestant American lunatics, not molesting good old (white Protestant) boys with guns. It skirts too around the fact that a striking proportion of the white American folk given to home-grown mass murder entertain and express deeply racist theories which say something unpleasant about American culture.

Likewise, here in Australia, we do not usually categorise the actions of a Martin Bryant or a Julian Knight as "terrorism". But we have no great difficulty in assuming terrorism of any homicidal or threatening acts by members of other ethnic groups, cultures and religions who decide that Australian society is an affront to their sense of themselves. Both NSW and Australian Federal Police spokesmen, for example, count the bizarre Lindt Café affair as one of their victories against terrorism.

Fifteen-year-old Farhad Khalil Mohammad Jabar must be considered to be a terrorist, even if we all dance around questions of whether he was religiously or politically motivated, or both, or whether he was the full quid. He certainly seemed to want to incite terror during the very moments that his skyrocket rose and fell, dealing death to a man who seems to have been a stranger to him.

He was, after all, Muslim, and of Middle Eastern descent, enough by itself for some people, including, one sometimes thinks, some journalists working for News Corp. Said to have been a docile and introverted student, he had recently become withdrawn and more noticeably pious in recent times, always, with Muslims apparently, a sure sign of impending trouble. A bit more than a week ago, he went from school to a Parramatta mosque for prayers, and appears to have met some men, one of whom gave him a handgun. Then he changed into Middle Eastern robes and went to the Parramatta police station where he shot a civilian accountant working for the police, before being shot in turn by a special constable.

He had been shouting jihadist slogans and seemed plainly bent on random murder and martyrdom. Yet, oddly, he was said to be of Kurdish background, not the usual constituency for followers of the Islamic State, if he was.

Investigations caused police raids on a few Middle Eastern households by the usual very large squadrons of NSW and federal police. A few people of Middle Eastern appearance were taken into custody, though most were later released uncharged. Many of these families had been raided after previous terror-associated incidents. Some had connections with Jabar (one, now released, was a classmate who is said to have exalted on social media about the murder of the accountant). Others were said to have been possible providers of the weapon made available to Jabar.

It was a measure of a change of prime ministers that the response from politicians, police and officials was restrained. One imagines that Tony Abbott would have brought in the army, interned Muslims, imposed strict "in-Parramatta" censorship, (adopted with enthusiasm by accountability-shy military chiefs) and declared that anyone against his "vigorous, but measured and limited" response was a traitor to Team Australia. No doubt against a background of 400 Australian flags specially provided by an eager and ambitious AFP hierarchy.

By contrast, Malcolm Turnbull was cautious, as was NSW Premier Michael Baird. Neither showed any tendency to use the incident to show that Labor was soft on national security. Bill Shorten did not return the favour; indeed for a moment, with his faux indignation and paedophilia references, looked as if he was going to try to manoeuvre his way to be on the right of Turnbull on terrorism. .

Even NSW Police Commissioner Andrew Scipione (sometimes a one-man jihad against anything of which he currently disapproves) was unable to be prompted into blaming religion. Scipione's enormous media team later produced, if out of shotgun range of each other, his two deputy Commissioners Ms Montague and Mr Capulet. Each was given a platform to ruminate on the war against terror. Mr Capulet, sounded rather more sensible, reasonable and fatherly, drawing attention to the youth of the malefactor. Assistant Commissioner Montague thought it unfortunate that the NSW Police did not yet have the power to keep every Australian under surveillance "24/7". There had been a time, of course, when a large subset of the NSW force, under her direction, had been engaged 24/7 watching and listening to Mr Capulet, (of Middle Eastern, but not Muslim, background) but, somewhat to her continuing surprise, it seems, was unable to detect any breaches of the law.

The most unexpected, and sensible intervention, came from Concetta Fierravanti-Wells, assistant minister for Multicultural Affairs, as parliamentary secretaries are called these days. Recently engaged in consultations to "deradicalise" militant Muslim youth, she appears to have noticed that abusing Muslims generally, in Abbott government mode, for gain in other constituencies is not the best way to win co-operation.

Heretically, she suggested that radicalisation of young people was a social issue and not just a national security problem. The radicals were getting younger, and many were disengaged, and off the rails.

She was asking, in effect, whether the Jabars of the world have a good deal in common with the Christopher Harper-Mercers of the world, even as, obviously, they have lots of points of difference. They seem to feel alienated, isolated, disenfranchised, bitter and angry at the world. Are these feelings as important as some interpretation of Islam in causing their actions?

Asking this is not moving to suggesting that terrorism is "our fault" or disputing personal responsibility by those who kill. But it may help us both to understand some of the conditions which seem to breed such cases (and, perhaps to do something about them) , and perhaps to identify (and deal with) those from whom we are at risk. This social environment is only one factor. Religious and cultural feelings and beliefs do help propel or impel the susceptible in particular directions. But most others (even of similar backgrounds) do not feel the same way.

It does not matter whether one is really persecuted. What seems to matter is the feeling of it. If they believe this, mere argument and evidence will often not suffice to remove the sense of grievance. Many more people in the world accept as broadly true a Muslim narrative of Western imperialism and occupation in the Middle East, and slaughter of Muslims, than who believe the generally accepted Australian narrative of our disinterested efforts to rescue Arabs from a death cult.

But expertise in identifying the alienated person susceptible to the call, internal or external, for action may not come from sophisticated understanding of Middle Eastern politics, the nuances of Islamic sects, or history or political science – the usual field of the national security "expert". It might come instead from psychology, common sense and the acute observation of friends and professional intimates. It might not be helped much – indeed may be hampered by – the surveillance of outsiders, particularly those whose instinct is to treat everyone as objects of suspicion. An over-intrusive counter-intelligence can, after all, increase the sense of themness and usness among those being monitored.

The security expert may be the one to make deductions about the directions in which a nominated vulnerable person may go, far less able to identify the loner in the first place.

Police and security specialists like to think that their training, understanding and street sense make them adept psychologists and shrewd judges. The mere fact that their currency is fear makes their self-assured and confident advice intimidating, for decision makers. The longer ministers deal with them, the more cynical they usually become, unless some secondary political purpose is being served.

Experience, not least after the opening of the files of security services, suggests that spooks habitually overrate their skills and judgments, and get away with it because they are so often subjected to genuinely critical scrutiny. Spooks can become masters of facts and things, events, patterns and words. But prediction has never been a forte, especially for ASIO. It's worse now that ASIO has become player as much as actor.

Likewise, the record of police detectives with discrete measurable crime, or with "proactive" policing, does not inspire confidence in the idea that they have special training or capacity in understanding the minds of anyone, least of all loners, the alienated, the mentally disturbed, or people of different cultures. Or, as the Mohamed Haneef case showed, that even the most senior tacticians have much in the way of calm or judgment.

The fabulous thing about "national security" is that one has seldom to prove anything, least of all to a court. Even assuming that our police and security services have saved us from untold plots, it has been at a fabulous price, social and financial. A fraction of the resources put into domestic violence, or tax fraud, might actually be seen to achieve something.