They accounted for 10 of the 22 dead, the youngest of them Saffie Roussos who was only eight years old. The bestiality of the mentality that could conceivably see her as any sort of foe and took her life along with the rest is beyond contempt.
The survivors will be honoured too, the 800 who were injured when Manchester-born Salman Ramadan Abedi, 22, detonated his shrapnel-filled bomb at a concert by singer Ariana Grande, knowing full well that her fans are mostly children who would certainly be victims.
Some of those survivors suffered life-changing injuries. Others bear severe psychological scars. They need no anniversary to remind them of the horror that unfolded on what should have been a joyous night out, because they live with its consequences every day.
And this is not an event that belongs to the past, however recent. It remains vividly of the present.
The investigation into it continues, with 100 officers still working full time, and the process under way to extradite the bomber’s brother, Hashem Abidi, from Libya to face charges of murder and conspiracy to cause an explosion.
It is not just Saffie and everybody else at Manchester Arena that night we remember and honour today, because May 22 marks another grim anniversary.
It was on this day in 2013 that Fusilier Lee Rigby, 25, also became a victim of terrorism, hacked to death in the street by Michael Adebolajo and Michael Adebowale near the Royal Artillery Barracks in Woolwich.
That a single day in spring is now marked for Britain by two acts of appalling savagery, both springing from the same perverted mindset, ought to act as a spur to the whole of society to do everything in its power to combat it.
We want no more anniversaries to commemorate like this, however respectfully, nor any more families to suffer as Saffie’s have.
Nor do we want any more entries in that heart-wrenching hierarchy of terrorist atrocities, which makes the Manchester bombing the deadliest after the July 7, 2005, attack on Underground trains and a London bus by four men, three of whom were from Yorkshire.
It comes as a jolt that it will soon be 13 years since the murder of 52 people simply going to work on public transport, which announced that large-scale terrorist activity with the aim of causing mass casualties had taken root in Britain.
Even more disturbingly, those years have demonstrated that the threat comes from within, in the form of our own citizens, born and raised here, yet whose minds have been warped into believing their country is not home, but an enemy state.
How deeply rooted this threat has become is shown by regular updates from the security services on its scale. There is seemingly no let-up in the number of people being radicalised and attempting to commit atrocities in the name of whatever ideology drives them.
The Prevent programme, intended to identify those at risk of radicalisation and intervene before minds can be poisoned, has – despite its critics – been a step in the right direction.
This is a shadowy battle, where the enemies are both the puppet-masters of extremism and disaffected, alienated and possibly mentally unstable people whose strings they are pulling.
Thankfully, the authorities have been successful in thwarting dozens of plots, but that is no consolation to the families of the Manchester victims or that of Lee Rigby as they mourn anew today.
But despite a decade and more of murder and grief, some who have a key part to play in the fight against terrorism continue to do too little.
Only last week, in a rare public appearance, MI5 director-general Andrew Parker called on internet companies to do more, urging them to take down sites with bomb-making instructions and warn the authorities of attempts to acquire components and chemicals that could be used to make explosives.
He could have gone further, and added that they should also remove videos intended to radicalise, as one of the most familiar elements of terrorism – whether by Islamists or far-right extremists – has been inadequate loners remotely brainwashed into violence.
There is a clear moral duty on web giants to do this, and if they will not meet it, the time has come for them to be compelled to do so by law.
If today’s anniversaries act as a trigger to the consciences of those who run internet companies, or stiffen the Government’s resolve to tell them in no uncertain terms to be more co-operative, then that would honour the memories of the dead.
The rest of us should honour them too, by stopping whatever we are doing, bowing our heads and remembering in silence.