The death of innocent civilians is nothing new in Afghanistan, but these 16 victims, nine of whom were children, were allegedly murdered by a rogue soldier, rather than the usual killers – drone attacks, air strikes and stray bullets. This incident has elicited rage among Afghans and westerners alike. But why are westerners not equally outraged when drone attacks kill entire families?

Drone attacks that kill civilians usually fall into our category of "collateral damage", because the dead civilians weren't specifically targeted, and we treat this category as an unfortunate consequence of war, not murder. Afghans see little difference – rightly so, in my opinion, because their loved ones are dead because of the conscious actions of Nato forces.

This distinction between collateral damage and murder seems to come down to the question of intent. Thomas Aquinas was one of the first to hone in on this distinction with his doctrine of double effect, which is still used today to justify collateral damage. It is believed in the west that some innocent death is excusable in war, as long as the deaths are not intended, and even if those deaths are foreseeable. But if civilian deaths are foreseeable in a course of action, and we take that action anyway, did we not intend them? I doubt Afghans would feel much consolation knowing that their family members were not directly targeted; rather, we just expected that our actions would kill a few people and it happened to be their family members – an unfortunate side-effect of war.

Yet, western audiences feel reassured knowing that most of the civilian deaths in Afghanistan were not intended; and they only become outraged when marines and soldiers clearly target civilians and kill women and children, urinate on their bodies, and plunder their body parts as trophies. From Abu Ghraib, to Fallujah, to Haditha, and now to Panjwai, US forces have committed massacres against civilians. These incidents stand out in the western mind, but to Afghans and Iraqis, they are no different from the daily slaughter of civilians by drones, air strikes, depleted uranium and stray bullets.

Tell a mother from Fallujah whose children have been horribly deformed by uranium weapons that her childrens' suffering was unintended, even though the health effects of uranium-based weapons are well-known. Tell the survivors of drone attacks that their dead family members were not targeted, and that their deaths were an unfortunate consequence of war. Is their pain any different from the father whose entire family was murdered in this most recent atrocity? If collateral damage is foreseeable, if it is really a fact of war, as most believe it is, is it not a crime to engage in war when it will inevitably kill innocents?

Is there really a morally significant difference between murder and collateral damage?

The consequentialist will argue that the good results outweigh the bad, that democracy, freedom and the liberation of Afghan women will improve the lives of Afghans so much that the deaths of a few are justified. This is an easy judgment for westerners to make from the comforts of their own homes; but it stinks of the same patriarchy and arrogance of the white man's burden that justified colonialism for so many years. Has anyone consulted Afghans and asked them if they think the good that the west has promised will come of this occupation is worth the lives of their family members?

The occupation of Afghanistan is an "atrocity-producing situation", as was the occupation of Iraq, and we have signed Afghans and Iraqis up for this against their will.

The nature of these occupations fosters atrocity. The invented enemy, the lack of a battlefield void of civilians, the supposed moral superiority of the occupiers, the obscure goals of the mission, the methods of training that prepare soldiers for occupation, and the methods of warfare all make the murder of civilians unavoidable. In modern warfare, 90% of the casualties are civilian, but this is a reality that the west likes to ignore.

Ross Caputi during the second siege of Fallujah, Iraq, in 2004

In my own experience, soldiers and marines face an unbearable quantum of pressure and responsibility, and this inevitably leads to atrocity. When I was deployed to Iraq in 2004, with 1st Battalion 8th Marines, we faced conflicting expectations from our leaders who wanted dispassionate obedience, from our society back home who wanted a Hollywood-style victory and a happy ending, from our families who wanted us to put their needs first, from our comrades-in-arms who wanted our loyalty, and from ourselves as we struggled to hold onto our humanity. As much we wanted to please everyone, we couldn't. We were only human, asked to bear inhuman burdens, and the result was inhumane behavior.

We often toyed with the ideas of suicide and homicide, and joked about them. We laughed at the possibilities that someday, we might end up homeless on the streets, or shooting bystanders from a bell tower somewhere. We knew these possibilities were real, and we were frightened by them. "Ah, the glory of it all," we laughed. It was dark humor that made the dark reality that many of us really were on the verge of killing ourselves or someone else easier to bear.

However, in occupied territory, violence that might otherwise be turned inwards, sometimes gets expressed outwards. In Fallujah, I witnessed all our frustrations, our loneliness, our grief, our confusion, hate, fear and rage being unleashed on Fallujah – and Fallujans paid dearly. I witnessed good people do horrible things. Almost anyone in such a situation would have become just as ruthless. Some of my closest friends mutilated dead bodies, looted from the pockets of dead resistance fighters, destroyed homes, and killed civilians.

Incidents such as what happened in Panjwai on Sunday cannot be chalked up to the actions of "one bad apple". Incidents like this one are the product of an immoral and inhuman occupation. The atrocities will not end until the occupation ends. When will we give up the illusion that war can be conducted humanely?