As I sat down to write this yesterday morning, there was breaking news of a mass killing at a residential facility for the disabled not far from Tokyo. The perpetrator was apparently a 26-year-old former employee of the care home who subsequently handed himself over to the police after murdering, according to initial reports, 19 people and injuring dozens of others.

Somewhat inevitably, a small number of comments on news media sites raised the possibility of Islamist motivation. There is every likelihood that it will turn out in this case to have been an absurdly misguided assumption. It’s not hard to trace, on the other hand, the genesis of this thought pattern.

It was even easier to jump to this conclusion in the wake of last week’s killing spree by a teenager in Munich. After all, David Ali Sonboly was a German of Iranian heritage. That sufficed, for all too many people, to assume that he was driven by religious fanaticism. According to the evidence that has surfaced so far, however, it appears that Sonboly was obsessed with mass shootings, especially at schools, and timed his assault to coincide with the anniversary of the Norwegian massacre five years earlier by Anders Breivik, who also went out of his way to target young people.

Breivik was ideologically driven, but not by “Islamism.” There is plenty of evidence, meanwhile, that Sonboly, who committed suicide after murdering nine people, was psychologically unstable. Yet the likelihood that his psychopathic tendencies did not originate in a particularly sordid interpretation of his ancestral faith does not necessarily set him too far apart from those who assume that the tenets of their faith oblige them to more or less randomly slaughter those whom they perceive to be unbelievers.

Among some shades of opinion, the tendency to investigate the psychological make-up of a killer is a variety of denialism, a studied refusal to condemn Islam as the invariable guiding force behind mass murder. This attitude in turn feeds into perpetuating the notion that all Muslims are potential terrorists.

It should not be particularly surprising that the latter assumption ideally suits the purposes of Daesh. The fact that Germany has lately allowed in hundreds of thousands of mostly Muslim refugees militates mightily against the notion of a West implacably hostile to Islam. If even a couple of refugees can be persuaded to perpetrate acts of indiscriminate violence, the hostility toward them can reasonably be expected to spread well beyond extremist outfits such as the Alternative for Germany (AfD).

The ax attack on a train in Wuerzberg by a teenage Afghan refugee (some news outlets claimed he was actually a Pakistani) on July 18 and, in the wake of Sonboly’s outrage, a pair of attacks by Syrian refugees — one of them killed a woman with a machete and injured five other people, while the other detonated a suicide vest near a music festival and, thankfully, succeeded in killing only himself — appeared, insofar as they may have been guided by Daesh operatives, to be directed toward propelling AfD’s agenda.

Much the same could be said about the singularly appalling attack in Nice on Bastille Day by Mohamed Lahouaiej-Bouhel, a Frenchman of Tunisian origin, who ploughed through crowds celebrating the national holiday in his massive truck, leaving more than 80 people — a third of them Muslims — dead and injuring many more. Unlike last year’s terrorist attacks in Paris, which tended to unite the French more in sorrow than in anger, the Nice outrage, amid a state of emergency, has more directly prompted an upsurge in antagonism toward the government of Francois Hollande, who responded crassly to the massacre by decreeing a more concerted military assault on Daesh redoubts in Iraq and Syria.

Should Marine Le Pen win the next French presidential election, a substantial proportion of the blame could be ladled on to Daesh, but Hollande won’t get away unscathed.

Europe’s far-right forces are effectively the other side of the Daesh coin. They may have divergent motivations, but the essential idea is to perpetuate the idea that there is little or no space for Muslims in Europe. The neo-Nazis are determined that there should be no place for Muslims in Europe. Daesh is bent upon ensuring that Europe is no place for Muslims, unless it is subsumed into the fantasy of a caliphate — whose territorial reach in Iraq and Syria is slowly diminishing.

There are also reasonable grounds, meanwhile, for questioning the dichotomy between Islamist fundamentalism and psychological dysfunction. The latter can, obviously, operate independently of the former, and the vast majority of people who diverge from what is assumed to be the norm in that sphere are obviously harmless, in the same way as most Muslims. But can murderous fanaticism be distinguished from a psychotic disorder?

Such a conclusion may complicate the task of dedicated anti-terrorists, but it’s not one they can afford to ignore.