Now that it seems likely the atrocity in Manchester was carried out by a freelance "soldier" allied to Islamic State, there's good reason to think neither the venue nor the performer were chosen at random.
Why would anyone target a concert by the American singer Ariana Grande? The grim answer may lie in the fact that with her revealing stage outfits, her stockings, pink bunny ears and unabashed sexual confidence, 23-year-old Miss Grande is a symbol of everything Islamists hate, according to Daily Mail.
According to the purist, medieval interpretation of the Koran favoured by Islamic State, almost everything about Western music, and the Western lifestyle that goes with it, is haram, or forbidden - and so merits a death sentence.
Indeed, one claim of responsibility for Monday's attack stated: "The explosive devices were detonated in the shameless concert arena."
Those unfortunate enough to live in Islamic State's caliphate have experience of this doctrine.
Three years ago, the then fledgling Islamic State issued a statement that read: "Songs and music are forbidden in Islam, as they prevent one from the remembrance of God and the Koran, and are a temptation and corruption of the heart." The directive went on to cite Koranic verses and Islamic teaching.
One young Syrian I met when I was reporting in the region, who lived in the group's de facto capital of Raqqa, told me dolefully his best friend was thrown in jail for wearing a Metallica T-shirt celebrating the U.S. rock band.
At the many checkpoints through which Syrians had to pass on their way out of Islamic State territory (back when they were allowed to leave), the militants paid as much attention to the length of men's beards and contents of their mobile phones as to their politics.
Guards, many of them no more than boys, diligently searched mobile phones for any minor infractions of their religious laws: and that included music that "insulted" Allah.
In their sliding scale of punishments, I was told, a single pop song was rewarded by between 30 and 40 lashes with a whip or stick.
In another incident in 2015, a group of musicians was reportedly sentenced to 90 lashes each for the 'crime' of playing an electronic keyboard.
Like medieval inquisitors, converts to the Islamic State see Satan (shaytan) and supernatural beings (jinns) everywhere and in anything.
In Syria and Iraq, their feared religious police (the hisbah) pay particular attention to teenage heavy metal music fans, which they consider the devil's work.
Women are treated as inherently suspicious, and are forced to cover up and wear the face veil when outside and never to leave home without a chaperone.
Thus the sight of Ariana Grande and her risque stage outfits would be anathema to the fanatics.
In territory controlled by Islamic State, everything from pop music to musical instruments are banned as totems of godless Western decadence.
That's why a group of masked Isis fighters were photographed two years ago in Libya - the country from which the Manchester suspect's family hail - burning a saxophone and drums.
Even before Islamic State moved to create its state in the ruins of Syria and Iraq, there were signs this extremist sensibility was taking root among disgruntled young Muslims in our inner cities.
In 2004, British police secretly recorded a cell of young Islamists discussing a possible attack on a London nightclub, on the basis that no one could "turn round and say 'Oh, they were innocent', those slags dancing around".
Likewise, a car bomb parked outside Tiger Tiger nightclub in London's Piccadilly in 2007 seems to have been designed to coincide with a "ladies' night" at the venue, in which the perpetrators might have hoped to kill and maim scantily clad young women drinking alcohol.
The vehicle was packed with 60 litres of petrol, gas cylinders and nails, and would have caused "carnage", police said, if the bomb had not failed to detonate.
(One great irony is that many of these young Islamists have a past of drug-dealing, debauchery and petty crime. Indeed, given all their injunctions against Western music, it's striking how many of those who travelled to the Islamic State from Britain - such as Londoner Abdel-Majed Abdel Bary, once photographed in Syria holding a severed head - were failed rap musicians.)
Now, as Islamic State territory in the Middle East is whittled away, its propaganda is urging supporters to strike back against "disbelievers" by seeking out more music venues and nightclubs.
So it was that an Islamic State gunman attacked a nightclub in Istanbul in the early hours of New Year's Day this year, killing 39 of that city's wealthy young set.
Islamic State also directed the appalling massacre of 89 people at the Bataclan concert hall in Paris in November 2015.
On that night, a gig by the U.S. rock band Eagles of Death Metal was targeted with automatic rifles, grenades and suicide bombs as the jihadis made a blood-soaked statement against Western music and the lifestyle that goes with it.
These Islamist puritans believe our Western way of life is on the verge of collapse and see their job as sending it to hell as quickly as possible.
Their war is not so much with our governments as with the values we all live by, which is why they are prepared to slaughter innocent little girls clutching pink balloons on a night out with their mothers at a pop concert.
James Harkin is director of the Centre for Investigative Journalism and a reporter on Syria and the rise of Islamic State.