One disconcerting effect of terrorism is that it makes us doubt ourselves, distorts the familiar and the obvious.

Martin Place, where before Monday the most pressing threat to health and safety was chronic overwork and executive stress, suddenly became a global spectacle of horror.

Even after spending 12 hours parked in front of the TV as the siege wore unbearably on, I could hardly believe my eyes.

Even now, in the sorrowful aftermath, there’s a lingering doubt in some quarters about whether this was terrorism at all.

The reticence around language made sense during the siege as the authorities had asked that certain information be withheld and particular terminology avoided.

The discussion was so mystifying that when the gunman forced his hostages to display a black flag with an Islamic message in Arabic, some reporters were circumspect about what this might mean.

It wasn’t an Islamic State flag, so how to interpret the gunman’s gesture?

I almost began to see the flag as an invitation to interfaith dialogue.

To set matters straight, we needed help from counterterrorism experts, political academics and cultural interpreters who suggested the flag be seen in context.

True, they said, the words on the banner carried a universal Islamic sentiment.

But, well, the man does have a gun.

He has taken hostages.

The flag is jihadist black.

He has forced his hostages to display it.

So, given all that, the experts said, it’s reasonable to conclude the man’s expressing an affinity with the cause of global jihad.

But though the blood of innocents has since dried, we’re still touchy about definitions.

Some people have called this a “terrorist attack”.

Others say that because Man Haron Monis was a “lone wolf” it isn’t terrorism.

Another columnist lamented that while Westerners were seen as complex creatures motivated by a range of factors, “such is the marginalisation of Muslims that they are not given the benefit of being individuals”.

Instead, Muslims “are often represented as a marauding horde, a grotesque collective that acts on nothing other than primitive, religious ideology”.

These are intelligent columnists but, on this occasion, I sense a paradox at the heart of their arguments.

To categorise Monis’ actions as those of an ordinary criminal rather than a religious extremist, we have to deprive him of the “benefit” of being an individual.

Monis had proclaimed his disgust for Australia’s military intervention in Afghanistan.

He sent abusive letters to families of deceased Australian soldiers who served there.

He converted from Shia Islam to Sunni, pledging allegiance to Islamic State.

During the siege he requested an Islamic State flag, obviously troubled that his banner wasn’t the pure article.

He demanded Tony Abbott refer to his actions as a terrorist attack.

It was prudent tactics to deny his self-definition during the siege, but to do so now is to flinch from reality.

The overriding narrative of the Sydney siege was not one of intimate partner violence.

True, Monis acted alone, no group rushed to claim credit for his actions. But in these anarchic, non-hierarchical times, more and more holy warriors are freelancers and loners.

Similarly, Monis should be seen as a violent criminal and a terrorist.

Together, “lone wolves” form a rabid pack.

Monis doesn’t need a certificate of authenticity signed by Islamic State.

Tragically, he’s more than proven himself on his own.