In the aftermath of Israel's lethal raid on the Free Gaza flotilla, a growing international consensus has emerged that Israel's three-year-old blockade of the coastal strip, home to 1.5 million, is unsustainable both morally and practically. Morally, because the notion of collective punishment of Gazans who voted, in largely free elections, for Hamas in 2006 seems not only repugnant but in its application is arbitrary and cruel. Practically, because far from engineering the fall of Hamas by putting Gazans "on a diet", as Israel had counted on, it has only strengthened the Islamic group.

As Israel's security forces detained another ship attempting to run the embargo, the Rachel Corrie, the justifications for continuing the blockade were becoming ever more convoluted. As Bradley Burston, an Israeli columnist wrote last week, it is no longer about Israel's defence but about the sterile business of defending the fact of the siege itself. It is worth recalling that the embargo was initiated not as a response to the rocket fire from groups in Gaza aimed at Israeli towns but in response to Hamas's seizure of power in Gaza from a Fatah movement that had attempted to block Hamas's popular mandate.

Israel has produced copies of restaurant menus from Gaza to show that the residents of the strip are not facing any real hardship. That is belied by rates of malnutrition now standing at 10%. Gaza's markets, the same material insists, are full too. Which is true as far as the claim goes. But those goods are at much inflated prices that only a minority can afford to purchase.

Now in the aftermath of the boarding of the Mavi Marmara, Prime Minister Binyamin Netanyahu and his ministers have furnished yet more justifications for Israel continuing with its siege: that an ending of the embargo would result in wholesale weapons smuggling, a legitimate concern, and the fear of the establishment of an "Iranian port" in Gaza, a quickly manufactured fantasy. Others have attempted to divert attention from the realities of Gaza further still, depicting the flotilla as a cynical attempt to "delegitimise" Israel.

History has shown blockades of this kind are rarely successful. Most notably, the decades-old US embargo of Cuba has achieved next to nothing. And the facts about Gaza are not difficult to establish.

It is a miserable and impoverished place, but not strictly starving as claimed by some activists campaigning against the siege. What exists are terrible humiliations. While Israel's Ministry of Foreign Affairs likes to boast about treating seriously ill Gazans in its hospitals, the process is so uncertain that patients have died waiting for approval. The aftermath of last year's Israeli war against Gaza left a legacy of widespread damage to homes, infrastructure and agriculture, the reconstruction of which Israel has blocked by preventing the passage of the materials required to rebuild.

Then there is the more pernicious impact of the embargo: economic, social and psychological. Before the blockade, much of Gaza's income came from the export of products such as flowers and strawberries and from day workers travelling to Israel. Fishermen, too, are prevented from crossing a maritime exclusion zone policed by Israeli gunboats, visible cruising along the coast. And in a place with crushing unemployment it is not only those at the bottom of the economic scale who have been punished by Israel's enforced "diet". In a society that puts much emphasis on education, the opportunities for a generation of young Gazans to pursue the careers they have been trained for are very limited.

The consequence has been the creation of an angry and frustrated society which has become ever more radicalised and has learned to associate Hamas – as it once associated Yasser Arafat and his Fatah movement – with resistance and national self-determination.

The bitter irony is that it is not only Gaza that has been damaged by the blockade. More than its two ill-fated wars in Lebanon, its numerous military offensives against its Palestinian neighbours, its targeted killings or even the construction of its separation wall, the prosecution of the blockade against Gaza – and the effort of justifying the unjustifiable – has corrupted Israel's own increasingly militarised political culture. With few exceptions until last week, most Israelis have demonstrated a shocking lack of interest in what is being done to Gaza in their name, echoing the general lack of empathy for those hundreds of civilians who died during Operation Cast Lead last year.

This can be explained in large part by the fact that Israel's leaders and government have fostered an almost permanent culture of conflict, insisting that their country is "at war" and in the frontline against an Islamist insurgency against the west, rather than embroiled in a long-standing political and territorial crisis with a security component. It has damaged Israel's diplomatic relationships to the extent that it has now alienated Turkey, its closest Muslim ally, and pushed the US, which had largely ignored Gaza since Barack Obama's inauguration, into calling for the blockade to end.

The critical issue is what the ending of that siege might mean. If the lifting of the blockade means only the inclusion of more items on Israel's list of goods that are allowed to enter Gaza, then the embargo will not have ended, it will only have been ameliorated. For it to be truly lifted, a far more humane approach to Gaza's residents is required. It should be one that allows them access to the outside world both for their goods and to travel; to develop as an economy and a society and to persuade Gazans that their home is not a prison but a place of opportunity.

For that to happen requires a wholesale change in Israel's mindset as well as that of Hamas. Hamas must be persuaded that as a broad movement it will lose nothing in accepting the right of Israel to exist. Additional measures should include the release of kidnapped Israeli soldier Gilad Schalit and the commitment to a long-term ceasefire which Hamas has long suggested that it can deliver.

Israel, no less importantly, must recognise that its default position on the deterrent value of the disproportionate use of military force to solve problems not only undermines its standing in the international community but is deeply counterproductive, putting Israel in more peril, not less.