There is no relief for the people of Haiti, it seems, even in their hour of promised salvation. More than a week after the earthquake that may have killed 200,000 people, most Haitians have seen nothing of the armada of aid they have been promised by the outside world. Instead, while the US military has commandeered Port-au-Prince's ­airport to pour thousands of soldiers into the stricken Caribbean state, wounded and hungry survivors of the catastrophe have carried on dying.

Most scandalously, US commanders have repeatedly turned away flights bringing medical equipment and ­emergency supplies from organisations such as the World Food Programme and Médecins Sans Frontières, in order to give priority to landing troops. Despite the remarkable patience and solidarity on the streets and the relatively small scale of looting, the aim is said to be to ensure security and avoid "another Somalia" – a reference to the US ­military's "Black Hawk Down" ­humiliation in 1993. It's an approach that ­certainly chimes with well-­established traditions of keeping Haiti under control.

In the last couple of days, another motivation has become clearer as the US has launched a full-scale naval blockade of Haiti to prevent a seaborne exodus by refugees seeking sanctuary in the United States from the desperate aftermath of disaster. So while Welsh firefighters and Cuban ­doctors have been getting on with the job of ­saving lives this week, the 82nd Airborne Division was busy parachuting into the ruins of Haiti's presidential palace.

There's no doubt that more Haitians have died as a result of these shockingly perverse priorities. As Patrick Elie, former defence minister in the government of Jean-Bertrand Aristide – twice overthrown with US support – put it: "We don't need soldiers, there's no war here." It's hardly surprising if Haitians such as Elie, or French and Venezuelan leaders, have talked about the threat of a new US occupation, given the scale of the takeover.

Their criticisms have been dismissed as kneejerk anti-Americanism at a time when the US military is regarded as the only force that can provide the ­logistical backup for the relief effort. In the context of Haiti's gruesome history of invasion and exploitation by the US and European colonial powers, though, that is a truly asinine response. For while last week's earthquake was a natural ­disaster, the scale of the human catastrophe it has unleashed is man-made.

It is uncontested that poverty is the main cause of the horrific death toll: the product of teeming shacks and the absence of health and public infrastructure. But Haiti's poverty is treated as some ­baffling quirk of history or culture, when in reality it is the direct ­consequence of a uniquely brutal ­relationship with the outside world — notably the US, France and Britain — stretching back centuries.

Punished for the success of its uprising against slavery and self-proclaimed first black republic of 1804 with invasion, blockade and a crushing burden of debt reparations only finally paid off in 1947, Haiti was occupied by the US between the wars and squeezed mercilessly by multiple creditors. More than a century of deliberate colonial impoverishment was followed by decades of the US-backed dictatorship of the Duvaliers, who indebted the country still further.

When the liberation theologist Aristide was elected on a platform of development and social justice, his challenge to Haiti's oligarchy and its international sponsors led to two foreign-backed coups and US invasions, a suspension of aid and loans, and eventual exile in 2004. Since then, thousands of UN troops have provided security for a discredited political system, while ­global financial institutions have imposed a relentlessly neoliberal diet, pauperising Haitians still further.

Thirty years ago, for example, Haiti was self-sufficient in its staple of rice. In the mid-90s the IMF forced it to slash tariffs, the US dumped its subsidised surplus on the country, and Haiti now imports the bulk of its rice. Tens of thousands of rice farmers were forced to move to the jerry-built slums of Port-au-Prince. Many died as a result last week.

The same goes for the lending and aid conditions imposed over the past two decades, which forced Haitian governments to privatise, hold down the minimum wage and cut back the already minimal health, education and public infrastructure. The impact can be seen in the helplessness of the Haitian state to provide the most basic relief to its own people. Even now, new IMF loans require Haiti to raise electricity prices and freeze public sector pay in a country where most people live on less than two dollars a day.

What this saga translates into in real life can be seen in the stark contrast between Haiti, which has taken its market medicine, with nearby Cuba, which hasn't, but suffers from a 50-year US economic blockade. While Haiti's infant mortality rate is around 80 per 1,000, Cuba's is 5.8; while nearly half Haitian adults are illiterate, the figure in Cuba is around 3%. And while 800 Haitians died in the hurricanes that devastated both islands last year, Cuba lost four people.

In her book The Shock Doctrine, Naomi Klein shows how natural disasters and wars, from Iraq to the 2004 Asian tsunami, have been used by corporate interests and their state ­sponsors to drive through predatory neoliberal ­policies, from ­radical deregulation to privatisation, that would have been impossible at other times. There's no doubt that some would now like to impose a form of ­disaster ­capitalism on Haiti. The influential US conservative Heritage Foundation initially argued last week that the ­earthquake ­offered ­"opportunities to ­reshape Haiti's long-dysfunctional government and ­economy as well as to improve the ­public image of the United States".

The former president Bill Clinton, who wants to build up Haiti's export-processing zones, appeared to contemplate something similar, though a good deal more sensitively, in an interview with the BBC. But more sweatshop assembly of products neither made nor sold in Haiti won't develop its economy nor provide a regular income for the majority. That requires the cancellation of Haiti's existing billion-dollar debt, a replacement of new loans with grants, and a Haitian-led democratic reconstruction of their own country, based on public investment, redevelopment of agriculture and a crash literacy programme. That really would offer a route out of Haiti's horror.