Two points stand out from Pat McFadden's career-killing question to David Cameron.

“ 'May I ask the prime minister to reject the view that sees terrorist acts as always being a response or a reaction to what we in the West do? Does he agree that such an approach risks infantilising the terrorists and treating them like children, when the truth is that they are adults who are entirely responsible for what they do? No one forces them to kill innocent people in Paris or Beirut. Unless we are clear about that, we will fail even to understand the threat we face, let alone confront it and ultimately overcome it.'

The first is that he did not mention Jeremy Corbyn, John McDonnell or Seumas Milne by name. But their petulant vengeance proved that he did not need to. Second, and more impressive and important than the petty politics of a doomed Labour party, was the precision with which he dissected a mindset that dominates the far left, and extends far beyond it across all parts of the political spectrum.

As McFadden said, Corbyn infantilises the non-white and the non-west. Radical Islam may be the fascism of our time. It may propagate and enforce misogyny, theocracy, racism and homophobia. But we cannot oppose it or offer the smallest sympathy to its victims. We should rather oppose ourselves. For we are responsible for their violence, because we have brought fascism back into the world by our greed, our violence and our imperialism.

In his Tyranny of Guilt, the French philosopher Pascal Bruckner emphasised the colonial mindset of 'anti-imperialists'. The West may no longer dominate the world. (We are the first 'imperialists' without an empire.) But they can maintain that the West still matters because it is the root cause of the world's ills. Psychologically, such narcissism is just about understandable as a compensation for decline. One day a cultural historian will notice that the explosion of chest-beating and garment-rending in the West coincided with the shift in economic power to east Asia. But as principled politics, the denial that there are reactionary movements and regimes in the world with motives of their own is a disgrace.

The questions pile up if you believe that non-western fascists movements are like infants with no responsibility for their actions. What of whites who join Combat 18 or the Ku Klux Klan, or confine themselves to supporting the BNP or the Front National. If they are poor, is their extremism their fault or the fault of their poverty and the society that allowed them to become and stay poor? If they are middle-class, are they the victims of a version of liberal multi-cultural imperialism which denies the validity of 'white culture'. How, if we are being consistent here, can we excuse the Islamist attacks on Paris, as 'blowback' as Seumas Milne does, but not the murders of white racists and fascists? Are they any less the toddlers, provoked by the wicked actions of the abusive grown ups into violent tantrums?

Then what of the victims of Islamic State or Al-Qaeda or their Shia equivalents in Baghdad, Damascus and Tehran? Rather than being allies, who deserve our support, everyone from Iranian socialists to Yazidi sex slaves, become disposable people, who must be remembered as the 'collateral damage' of Western foreign policy – assuming, that is, they are remembered at all. Their fate is to be murdered or oppressed until that time in the future when the West atones for its sins.

I think it is fair to say that Corbyn has spent most of his life in the dusty meeting halls where the far left gathers, and has never once asked himself a hard moral question. Here he is after the 7/7 attacks on my fellow citizens here in London:

And here he is after the Russian annexation of the Crimea and invasion of Ukraine:

“ NATO has sought to expand since the end of the cold war. It has increased its military capability and expenditure. It operates way beyond its original 1948 area and its attempt to encircle Russia is one of the big threats of our time.

It's not that Corbyn and his kind unequivocally support Putin or call for British Muslims to turn to terrorism, but that he continually infantilises and excuses them. Given our perfidy we really left them with no choice.

You may object that Western foreign policy is often immoral and frequently stupid, and there is nothing wrong with opposing it. Indeed there is not. But if your opposition consists of adopting every argument Putin would make about the Ukraine or every justification of a recruit to Islamic State, you become no different from them.

I have a piece in the current issue of Standpoint on the appeasing mentality. It ends thus:

“ Anyone can play the game. You can say the attacks on the World Trade Centre and Pentagon were a rational response to American support for Saudi Arabia and Israel. If America wanted to be safe, it should stop supporting Saudi Arabia and Israel. The British Left claimed that the 7/7 attacks on London were a rational response to British involvement in the 2003 invasion of Iraq. It wasn’t true: Mohammad Sidique Khan, the terrorist cell’s leader, was training in Islamist camps long before the Iraq war. Nevertheless, the point still held: you can suppose that Western foreign policy provides a “rationale” for Muslims who become terrorists. You can say, as John Kerry implied, that if Charlie Hebdo had steered clear of Islam, it would never have been bombed. You can say that Jews would not be targets if they renounced Judaism. You can say that Islamic State would not have attacked Paris if the French had stayed out of Syria. You can say that the existence of Israel explains Hamas. You can say that IS would not treat Yazidi women as sex slaves if they had embraced its version of Sunni Islam. You can say there is a rationale for the Iranian subjugation of its Sunni minority and the Saudi subjugation of its Shia minority, for both are potentially dangerous to their respective states. You can say that Muslim countries would not persecute homosexuals if they went straight, or order the death of apostates if they remained good Muslims. There is no limit to the number of reasons you can find. Every time you rationalise, however, you miss the obvious and ignore an often openly fascistic ideology whose appeal lies in its supernatural certainties and totalitarian promise of a new heaven on earth.

Every step you take explaining radical Islam away is apparently rational and liberal. Each takes you further from rationalism and liberalism. In your determination to see the other side’s point of view and to avoid making it “really angry about this or that”, you end up altering your behaviour so much that you can no longer challenge the prejudices of violent religious reactionaries. As you seek rationales for the irrational and excuses for the inexcusable, you become a propagandist for the men you once opposed.

Pat McFadden is better off without Jeremy Corbyn. I just wish I could say the same about the rest of the Labour party.