After the atrocity, the agonizing. How could someone do such a thing? Is our foreign policy to blame? Why don't moderate Muslims condemn terrorism? Why don't they report suspicious behavior? Do we need to change our immigration policy? Are we unprepared for the next attack?

These questions are a form of displacement activity, a way of not thinking too hard about the horror. Just try to hold in your mind what happened. A room full of teenage and pre-teen girls, girls who have spent months waiting for that evening, Snapchatting each other, planning what they're going to wear, girls who had skipped happily away from their parents, full of expectation, only to end the night maimed, lacerated or dead.

I'm sorry: I know it wasn't fun to read that sentence. Believe me, it wasn't fun writing it. If you have daughters of that age, as I have, you will have seen them in the face of each newly-identified victim. And your thoughts, like mine, will have veered away. We can take in only so much grief. So, instead, we run through the usual litany of questions.

How could Salman Abedi target children holding pink balloons? We might as well ask how Adam Lanza could murder the kids at Sandy Hook, or Thomas Hamilton those at Dunblane. There are wicked people, people outside the norms of human morality.

Was it our fault? Oh, for heaven's sake, how many times? Abedi's parents were given sanctuary in Britain because they had been persecuted in Libya by Moammar Gadhafi. As if that wasn't enough, Britain then took the lead in ousting the mad colonel. Abedi's sister was quoted as saying that he might have wanted "revenge" for Muslim kids killed in Syria. That would be the Muslim kids killed by Bashar Assad, whom Britain is also working to remove.

In short, he had every reason to be grateful to the country that had given him refuge and freedom.

I'm not sure which kind of solipsism is uglier: that of the Islamists (Muslim suffering is the fault of the West), or that of the self-hating British Left (all suffering is the fault of the West). Either way, the two forms of narcissism prop each other up.

Why don't mainstream Muslims speak out? They do. British imams have repeatedly pronounced fatwas against Daesh. The Muslim Council of Britain, the chief Islamic confederation in the U.K., responded unequivocally to the bombing: "This is horrific, this is criminal. May the perpetrators face the full weight of justice both in this life and the next."

Why don't Muslims report potential extremists? Again, they do. We now know that several local Muslims had told the authorities that they were concerned about Abedi's radicalization, and that he had been kicked out of his mosque after taking issue with an anti-extremism sermon.

Should we change our immigration policy? There may be a case for doing so anyway, but Abedi was born in the U.K. The last two jihadi assaults on British soil which led to fatalities — indeed, the only two since the Tube bombings 12 years ago — were the knife attack on Parliament in March and the murder of Private Lee Rigby in Woolwich four years to the day before the Manchester bombing. Both those abominations were carried out by Britons who had converted to Islam — or, rather, to Islamism, since nothing in their behavior suggested conventional piety.

Can we do more to prevent attacks like this? Here is perhaps the hardest thing to say. Nothing can stop a suicide bomber who has picked a soft target. Suppose we had metal detectors and security checks at every sports stadium and concert hall. The line of people at the checkpoint would then become vulnerable, as we saw in the Brussels airport bombing.

In any case, how could you possibly secure every shopping mall, every busy street? All you can do is keep track of the potential terrorists — something which, in general, we are doing pretty well. Although this attack ended in carnage, dozens have been thwarted.

We are improving our security techniques. We are working with moderate Muslims to keep tabs on potential extremists. We are infiltrating and dismantling terrorist networks. We have dropped the woolly-minded multiculturalism that stood in the way of assimilation. Ultimately, though, nothing can stop a determined killer from hitting a foyer full of kids and parents. Sometimes, we just have to acknowledge that evil is part of the human condition in this life and hope, with the Muslim Council of Britain, that there is justice in the next.

Dan Hannan is a British Conservative MEP.