The grisly spectacle of Muammar Gaddafi's death and posthumous career as Misrata's most popular body art exhibit may not have been very edifying, and news that the deposed dictator of Libya has been quietly buried at a secret desert location has to be welcome. Let's hope the disposal of his decaying remains does bring an end to the surreal story that started with ambiguous video images – was he dead or alive? – and culminated with shots like that shown here of celebratory people eager to view the bodies of Gaddafi and his son Mutassim in a cold storage unit, surrounding the corpse to photograph it on their phones.

But nothing in the photographs of Gaddafi wounded, dead, dragged through the streets, and finally on display, rotting in public, has been anything like as disgusting as the thoroughly hypocritical and self-deceiving international reaction to these pictures. Libyans did what they probably had to do. Their western supporters have moaned and groaned at the realities of war with no apparent understanding that through Nato we are participants in this conflict and so share its inevitable moral complexities.

First our media rushed the confusing visual evidence of Gaddafi's capture on to websites and into print. Then, as the reality that he was dead became clear, it worried about the ethics of so openly displaying photographs and video of a corpse.

Meanwhile global agencies expressed concern over the mystery of Gaddafi's killing. Libya's National Transitional Council (NTC) came under pressure to hold a proper inquiry, and evidence of more executions in the last days of fighting was sternly announced. By the time Gaddafi's body was said to be finally heading for desert burial, the manner and imagery of his death threatened to absorb the larger story of Libya's liberation.

The Arab spring became The Autumn of the Patriarch, as his dead body haunted the new era. No wonder a Libyan was quoted as saying he has given more trouble dead than alive. Yet the main trouble dead Gaddafi has given is to expose the fundamental shallowness and sentimentality of the western democracies' support for Arab revolution and in particular our military intervention in Libya.

To get upset by photographs of the dead Gaddafi is to pretend we did not know we went to war at all. It is to fantasise that our own role is so just and proper and decent that it is not bloody at all.

Why is the modern western world so obsessed with the idea of a "just war", which goes back to the medieval theology of Thomas Aquinas? In the 21st century we keep trying to re-enact some fantasy of a war that is utterly righteous, and from which we emerge with no guilt on our hands – not even the killing of a brutal dictator. Gaddafi should have gone on trial at The Hague, we wail. He should have been decorously imprisoned and politely handed over to international war crimes judges. It's complete nonsense. We totally forget the fact that Nato planes blasted his Tripoli control centres with every chance of killing him. If a French or British raid just happened to have blown him to bits, would we be wringing our hands?

The stench of doublethink is more noxious than any vapour emerging from the meat store in Misrata. When I look at this photograph what do I see? War. War and nothing else. How many times do we need to be told that war is hell? The phrase has lost all meaning for us. Think about what hell is. Hell, in paintings by Bosch, is chaos. It is meaningless, monstrous, and lacks any place of safety or redemption. This picture of Gaddafi dead is a day in the life of hell, also known as war: a corpse photographed for souvenirs, displayed to satisfy the oppressed, in a moment of violent gratification. When Nato intervened in Libya what we see in this picture was probably the best – not the worst – outcome on offer. And we should be grimly glad of it. What fantasy makes us long for some impossibly dignified and humane end to a bloody conflict?

The west's dangerous delusion that war can be a decent and worthwhile activity is shaped by false memories of the second world war. "The Good War" was good only in self-congratulatory myth. In reality it was the most murderous conflict in history, destroying unimaginable numbers of civilian lives from Dresden to Auschwitz to Hiroshima.

Other popular myths of modern war are just as false. The republican cause in 1930s Spain was undoubtedly legitimate, Franco's victory over it a tragedy. But to this day, nostalgists for republican Spain avoid dwelling on atrocities done in its name against the clergy. Nationalists exaggerated the numbers but it is nevertheless known today that Republicans murdered 4,184 priests, 2,365 male members of religious orders, 13 bishops and 283 nuns. Somehow those figures are forgotten when Joan Miró's poster of a revolutionary peasant is displayed at Tate Modern.

Why have the photographs and films of Gaddafi's end caused so much fuss and bother? Because they show us the reality of war that we are usually so good at ignoring. In 10 years of wars since 9/11 the worst pictures, the trophy images of the dead and grotesque scenes of roadside slaughter, have been kept away from the mainstream media, to be sought on the internet by those who wish to sup on horrors.

But for once, with the death of Gaddafi, we have seen the face of war, washed in blood, bathed in cruelty. The horrible and haunting pictures of his last moments and his public exhibition simply show us, for once, what the wars of our time and all times look like. If we don't like what we see we must stop this foolish pretence that war, however "just", can ever be anything but a brutal mess.