We should all be bothered by Hilary Mantel’s short story “The Assassination of Margaret Thatcher”, published in the Guardian last Friday, and the reception it has got. The thought behind it, if I read it right, is that Hilary Mantel was so angered by Thatcher during her premiership that she even wondered whether assassination might be an appropriate response. She has now written a story, set in 1983, in which assassination actually occurs.

The defence of this is partly that all is fair in love and fiction, and I’m fine with that. What I’m not fine about is the dignifying of the idea that killing or any form of extreme violence is legitimate in the face of a political opponent engaged in policies with which one disagrees.

Mantel’s view appears to be that Thatcher’s evil was so extreme that the only reasonable response was hatred and, consequently, the extreme measures that hatred gives rise to. More than that: that the proof of Thatcher’s evil is the violence of the rage that it inspired. To rephrase this, that the proof of Thatcher’s evil is the fact that a good and moral person like Mantel could be roused to a violence that goes way beyond how we think of her and how she thinks of herself, normally such a mild, kindly person.

This is terrible, and I’m not at all sure that Mantel knows why, but I can give three illustrations from other contexts that might explain it.

I once heard the radical Nation of Islam leader Louis Farrakhan at a rally in Fresno, California. At one point, he asked a rhetorical question of the Jewish world: “What did you do,” he asked, “to make Hitler hate you so much?” I think Mantel’s short story asks the same question of Thatcher: “What did you do to make me hate you so much?” The hatred and what comes of it, in other words, is regarded as a justified response to an otherwise unanswerable provocation.

We’ve heard the same argument raised this summer by ISIS of the West. “What did you do, America, or Western capitalism, or imperialism, to make us hate you so much?” ISIS’s view is that its response to the West, however barbaric, cannot be compared with the evil that caused it. Indeed, that it is excusable because it is the only reasonable response – the response of a victim pushed beyond his or her endurance.

And the third example? That of opponents of Israel in the Arab, and Palestinian and now, regrettably, the wider Islamic world: “What did you do, Israel, to make us hate you so much?” If we maintain a continuous policy of aggression towards you, that’s OK because of what you have done to us. In fact, it is proof of your evil that we – the innocents of Palestine and of the surrounding 430 million Arabs and billion Muslims – have been roused to such anger. We’re good people, nice people, “generous people who have lost almost everything” (to quote the BBC’s Jon Donnison): only an evil as intense as yours could have made us feel so bad that wiping you out becomes the only answer and the right answer.

This, of course, is also the Jenny Tonge argument, and the David Ward argument, and the George Galloway argument. Negotiation and conventional politics don’t apply because your evil only warrants one reaction: our murderous rage.

It is a gross distortion of political logic that should bring us all up short. We’ve been afraid of what might happen when radicalised Muslims go off to Sudan or Syria or Afghanistan to train, and then import their radicalism back to the West. It didn’t occur to us that a copycat form of radicalisation has already infiltrated our own nice, polite, liberal intelligentsia – the people that many of us grew up with and consider our friends.

If you’re in any doubt, read the Guardian online and look at how comments about this are playing out. And then call the children in from outside, lock the doors and worry.