Friends of Israel have long lamented the apparent numbing of its moral sensibility, seeing it as an insidious long-term consequence of the country's interminable-seeming conflict with the Palestinians. They will feel renewed concern following the publication yesterday of an Israeli report into last May's raid on the aid flotilla bound for Gaza. Public opinion throughout the world largely deplored the violence with which Israel enforced its blockade of the Hamas-ruled enclave and stopped the convoy, leaving nine Turkish civilians dead.

Israel's response is a report that exonerates the military with only a few caveats and pats Israel on the back, not only over the conduct of the raid but over the blockade of Gaza in general. According to the Turkel Commission, this breaks no international law. Not surprisingly, Israel's political establishment is delighted. The Defence Minister, Ehud Barak, has congratulated the commission, declaring that the report "proved Israel is a law-abiding country".

Many will feel that the report proves nothing of the sort, but only highlights a growing unwillingness on the part of Israel to subject the actions of its military in Gaza and the West Bank to scrutiny. As we report today, 52 separate military police investigations over the last two years into Israel's December 2008 offensive in Gaza, Operation Cast Lead, which resulted in the deaths of 759 Palestinian non-combatants, have yielded precious little. The level of casualties in the offensive was shocking.

A single lethal air strike on a house where about a hundred civilians were sheltering killed 21 of them. There were well-documented cases of Israeli troops using children as human shields. These were corroborated in some instances by Breaking the Silence, a group of Israeli human rights activists and former army veterans, some of whose members witnessed these events.

A country that resorts to such inhumane tactics while presenting itself as a standard bearer for democracy should be asking itself hard questions about whether it was striking the right balance between security demands and respect for the basic human rights of civilians caught up in a war zone.

That does not seem to be happening. With most investigations into Operation Cast Lead already closed, and only one soldier jailed in connection with the events – for a trivial offence – Israel has clearly decided that in the run-up publication of a UN report into the Gaza bloodshed of two years ago, attack is the best form of defence. The UN report is likely to be critical but Israel will be able to dismiss it as biased, citing its own investigations.

The most immediate losers in all this are the relatives of victims of the raids on Gaza who have been denied justice. Unfortunately for them, Israel is unlikely to come under much pressure to explain its actions more convincingly. In America, even light-touch criticism of Israel is politically fraught, while in Europe and most Arab capitals, fear of giving succour to the Islamist regime that rules Gaza is an overriding preoccupation. When it comes to Gaza, Europe tends to turn a blind eye to actions by Israel that it would condemn elsewhere.

If, as seems likely, no one takes much notice of the conclusions of the UN report into the offensive into Gaza, Mr Barak will no doubt feel even more relieved than he does today. So will the Hamas authorities who thrive on the culture of martyrdom and who justify their rigid hostility to Israel by pointing to the flagrant injustice with which Israel – and most of the world – treats Palestinians.

By failing to come clean over Operation Cast Lead, or over the Gaza flotilla, Israel neither advances its own cause nor that of peace in the region.