As the Metropolitan police flit off – somewhat pointlessly – to the borders of northern Syria in search of three teen Isis fangirls from Bethnal Green it’s hard for good liberals like myself to know where to chivvy blame.

It’s Twitter’s fault, reportedly. Twitter helped these girls connect with other gleeful fans of snuff-video beheading, cage-burning and the hobbysport of hurling gay men to their deaths from towers. Let’s blame Twitter. Sure, if Twitter shut up shop tomorrow – turfing off its 284m users – then Isis would use other social media platforms, but as none of those platforms are as famous as Twitter, it makes less sexy news.

Or is it Theresa May’s fault? Bad, culpable Theresa. Not once did this woman drive personally to any of these teenagers’ homes, check their Internet search histories and text messages, or give them a pep talk on why the mass beheading of Christians is simply not on. Or is it my fault for not shouting loud enough on a Stop the War demo? Or is it Turkish Airlines’ fault for not stopping and searching every young, brown woman trying to leave the country alone. Hang on, that’s actually racist and sexist. Scrap that. Gosh, this is confusing.

S ome people must be wondering if the parents of Amira, Shamima and Kadiza are to blame. They appeared on TV this week, some clutching teddy bears belonging to their little blossoms, presenting them as easily-confused delicate ingenues. This differed, to my mind, from the cool-headed, elegantly pulled together, determined young women I’d watched the footage of on CCTV. Not silly kids wagging off school, but calm, considered, A-grade students who have researched their trip, found hundreds of pounds in funds, booked flights and headed towards earth’s closest vision of actual hell.

In Isis we are observing a level of atrocity towards mankind that, post-Nazism, we hoped we would never again witness. But with Isis there’s no excuse for not knowing what “they” are up to. There will no big post-war reveal where we can wring our hands saying, “Well, this is awful, but we had no idea”. I wanted to ask Abase Hussen, as he clutched his daughter Amira’s stuffed toy, what exactly he thought was the tipping point that made his delicate, innocent baby-girl leave the country in such a rush that she left teddy behind?

Was it the video of Alan Henning – a man who stood for nothing but kindness – having his head removed? Was it photos of crucifixions of in central Raqqa? The reports from Kobani of raped, mutilated six-year-old female corpses lying in the streets? Which image of a future life excited her the most? Submissive jihadi bride with a big strong executioner boyfriend? Machine-gun toting trained killer? And all this without her teddy bear? Thank heavens we know she uses Twitter. She can tweet Clintons Cards and see if they’ll post out a replacement Mr Fluffy. How will princess sleep without?

Anti-Isis demonstrations across Europe Show all 10 1 /10 Anti-Isis demonstrations across Europe Anti-Isis demonstrations across Europe Anti-Isis protests in Ankara, Turkey A person holds a flag as police uses tear gas and water cannon in Ankara against demonstrators who protest against attacks launched by Islamic State insurgents targeting the Syrian city of Kobani and lack of action by the government Anti-Isis demonstrations across Europe Anti-Isis protests in Diyarbaki, Turkey Protesters clashing with riot police during a demonstration against Isis in Diyarbakir, southeast of Turkey Anti-Isis demonstrations across Europe Anti-Isis protests in Diyarbaki, Turkey Kurdish protesters in the southeastern city of Diyarbakir Getty Images Anti-Isis demonstrations across Europe Anti-Isis protests in Diyarbaki, Turkey Kurdish protesters clash with Turkish riot policemen in the city of Diyarbakir Getty Images Anti-Isis demonstrations across Europe Anti-Isis protests in Brussels, Belgium Riot police block Kurdish protesters as they gather in front of the entrance of the European Parliament in Brussels AP Anti-Isis demonstrations across Europe Anti-Isis protests in Berlin, Germany Demonstrators, including one holding a sign that reads: "Save the Kurds of Kobane from IS," and many of them members of Berlin's large Kurdish community, march to protest against the ongoing violence by militias of the Isis in Iraq and Syria in Berlin Anti-Isis demonstrations across Europe Anti-Isis protests in Hamburg, Germany Kurds protest against Isis militants advancing through the Syrian border city of Kobani, in Hamburg, Germany Anti-Isis demonstrations across Europe Anti-Isis protests in London, UK Kurdish protesters gather at Heathrow Airport as anti-Isis demonstrations take place across Europe Lisa Campbell Anti-Isis demonstrations across Europe Anti-Isis protests in Paris, France Kurds living in France demonstrate in Paris Anti-Isis demonstrations across Europe Anti-Isis protests in Marseille, France Kurdish people hold flag in Marseille during a protest against the threat of a "Syrian Kurdish population's genocide" by Isis militants and to support the population of the Syrian Kurdish town of Ain al-Arab, known as Kobani

Abase Hussen, and the rest of the families, are adamant that there were no signs that their daughters were plotting. That means, I surmise, no suspicious internet windows left open, no dubious items in search histories, no odd phone-calls, no suspicious comments at the dinner table, no new friends suddenly in the social circle, no mysterious requests for extra money, no mysterious selling of personal items to raise funds, no bizarre text messages, no rooting through drawers for passports, in fact, absolutely nothing remarkable at all. I have no reason to disbelieve the families, but this was a startling ruse to pull off. When I was 15 my family – via the Dent family mother-sibling Stasi network – would have sussed I was heading to Turkey before I’d even decided myself.

Of course, there’s a strong case to be made that fleeing abroad in search of Isis is simply a severe case of teen rebellion. Much, in fact, like the time, aged 15, when I pierced my nose and dyed my hair a sort of toxic cyan shade, imagining myself to look like a sexy mermaid, like Kate from The B52s, but instead resembling the Cookie Monster. I was a complete tit for almost all of the 1980s. The Nineties and Noughties were only marginally better. But still, I am lost for ideas on how we greet young teen rebels who hope to return here after mixing with Isis.

If the sight of gay men plummeting to their deaths excited you so much that you went and spent five years aiding and abetting the homophobic carnage, forgive me, but I don’t want to come across you in Bethnal Green Tesco Metro. I can’t imagine that time spent hanging out with horror-movie ghouls who hate Britain, gays, democracy, the rights of women and religious freedom will have done much good for your personal development.

I’d go as far as to say you shouldn’t be allowed back into the country ever, when surely there are dozens of other bloodier, more depressing places that suit your lifestyle choice better. However, I’ve asked my liberal friends what we should do and they all wring their hands and say after some mumbling, “Nothing.” So give me a call when you’re bored with all the stoning, crucifying and beheading. I’ll meet you at Heathrow Arrivals with your teddy.