I've spent the last couple months promoting In Our Mad and Furious City. I've often had a variation of the same question: why attempt to understand our monsters? Why write any book that refracts something like violent extremism into sympathetic characters?

I've spoken a lot about the killing of Lee Rigby. How my identification with one of his killers - the Islamic extremist Michael Adebolajo - acted as the catalyst behind the novel. The initial reaction was simplistic: Adebolajo dressed, spoke, and looked like any number of young men I went to school with. It disturbed me.

What's been difficult to articulate is why I then felt compelled to write toward that disturbance. Why did I think it was important to write about violent extremism not as some social aberration but as a deeply human compulsion? Why attempt to transpose it alongside other manifestations of extremism - in fiction?

This evening I finally sat down and watched Deeyah Khan's exceptional documentary White Right: Meeting The Enemy. One of the individuals featured was Pardeep Singh Kaleka whose father was murdered by the far-right extremist Wade Page.

As the documentary shows Pardeep's response to his father's killing was surprising. He reached out to the ex-far right extremist Arno Michaelis. He sought to understand Wade Page, the man who took away his father. He met and became friends with Arno Michaelis whose own background included similar violence and extremist ideology.

At one point toward the end of the film, Pardeep and Arno are talking. Arno says he sees a lot of himself in Wade Page. He goes on to explain that if he hadn't chosen another path, he himself could've acted in a similar fashion. He'd have become a killer. What Pardeep said next struck me. It was a variation of what I've been desperately trying to articulate:

"It doesn't surprise me that Arno sees himself in Wade Page. What surprises me is that we - [meaning all of us] - don't see ourselves in Wade Page. When we don't see ourselves in that person, then we lose our ability to do anything about it."

So why attempt to understand monsters? Because they're our monsters. Let me be clear: I'm entirely uninterested in understanding how men like Michael Adebolajo, Salman Abedi, Thomas Mair become extremists. But I do know that by distancing that pathology from ourselves the way we do - calling them inhuman, monsters, lunatics, supposed products of some inherently violent religion or culture - we end up abdicating our own responsibility. They're just as human as I am. That is what makes their acts so despicable.

Seeking to confront violent pathologies doesn't excuse or diminish monstrous acts. It confronts the ugliest side of ourselves so that we may do something about it.

White Right is available to watch on Netflix.