Before what happened in Christchurch, Jacinda Adern was a name we knew for various small reasons. She seemed young at 38 to be running New Zealand’s government; she gave birth when new to the job and then took her three-month-old daughter to the United Nations General Assembly; and she talked liberal good sense with a smile.

Since last week’s carnage when a gunman killed 50 people, and injured many more, Adern has excelled at a role no leader wants, that of taking her country by the hand after a national tragedy.

Her manner and her words have been what is required, and sorrow has been etched on her face in place of that easy smile.

Words are important at such moments, and Adern has spoken well. This was first apparent when she said that Muslim immigrants had “chosen to make New Zealand their home, and it is their home. They are us. The person who perpetrated this violence is against us, is not us…”

Simple words are the strongest words and three stood out: “They are us.”

We should repeat those words when they no longer seem so important; we should recite them alongside those now famous words the murdered Labour MP Jo Cox said in her maiden speech – “We are far more united and have far more in common with each other than things that divide us.”

“They are us” and “far more in common” – sensible and compassionate words from woman politicians, one who paid with her life, thanks to another right-wing extremist.

I am not going to name the man who killed Jo Cox, and this is in part thanks to a sensible proclamation this morning from Jacinda Adern.

The way extremists become grubby gods in memory has always troubled me; the way that their names with repetition acquire a sort of soiled sainthood. It’s as if we are in too much of a rush to install them in the world’s house of horrors, where Jack the Ripper always holds court – something the author Hallie Rubenhold is attempting to put right in her new book The Five, which records “the untold lives of the women killed by Jack the Ripper”.

All books need an angle and Rubenhold’s is a good one: remember the victims not the killer.

And that’s what Jacinda Adern has just said, vowing to never again say the name of the Christchurch mosque gunman. “He sought many things from his act of terror, but one was notoriety – that is why you will never hear me mention his name,” Ardern said in an emotional address at New Zealand’s parliament.

This seems exactly right to me, even if the report on the BBC website quoted her wise words – and then repeated the killer’s name again, undoing the point she was trying to make.

Actions count too, of course. Adern has already said that New Zealand’s gun laws will be changed, suggesting that semi-automatic weapons will be banned, as they already are in Australia.

In my simplistic world view, there is no reason for anyone anywhere to have any sort of gun; and there is absolutely no reason for the public sale of military-style semi-automatics – weapon of choice for cowards everywhere. Ban the lot of them; mash them up; melt them down.

And don’t name the white supremacist moron who inflicted such death and misery on the innocent Muslims of Christchurch. And, if Netflix happens to be reading, don’t start planning a gruesome documentary about the man behind the mass murders. He deserves only long obscurity behind a locked door.

And, yes, not naming people is tricky for journalists. But some names don’t deserve to be spoken.