They were not, as Israel's defence minister Ehud Barack ludicrously tried to claim, "an armada of hate and violence".

Nor was the Mavi Marmara "a boat of hate", as Israeli prime minister Benjamin Netanyahu described the Turkish ship, trying to justify his commandos gunning down nine civilians on board as they stormed the boat in international waters.

But Netanyahu was right on one count. "This was not a love boat."

The Free Gaza flotilla has been classed by some as a bunch of well-meaning but misguided hippy activists who want to spread peace and love and do not understand the delicate balances of power within the Middle East region.

The movement is far from that, and legitimately so.

These are well-informed, sincere and highly-motivated people who have come together from across the globe to muster the refreshing force of people power. They know that, in the absence of any meaningful moves at governmental level to force Israel to dismantle its illegal blockade of Gaza and to pressurise both Palestine and Israel to take part in peace talks, 1.6 million inhabitants of Gaza will continue to live in desperate conditions, their access to food and supplies reliant on the whim of the Israeli authorities.

The flotilla carried a humanitarian cargo, but it was ultimately, and powerfully, political.

The Free Gaza organisation knows full well that action to enforce United Nations Security Council Resolution 1860, which calls on Israel to dismantle the blockade of Gaza, will never happen because the blockade is a product of the very foreign policy these countries promote.

It knows that neither the US nor Europe will do anything to pressurise Israel into meaningful talks with Palestinian leaders which, now that the Palestinian Authority has lost all authority in the Gaza strip, must include Hamas in some context.

As a result, the flotilla could not simply offload its cargo at the Israeli port of Ashdod and hand over the aid. It could never be merely a humanitarian mission. The boats had to publicly challenge the blockade itself in order to highlight its illegality and its effect on the people of Gaza.

The mistake Israel made was to act against the citizens of 40 different friendly nations, including many high-profile individuals, in the same way as it generally reacts to those who oppose it in Lebanon or Gaza – with lethal force.

The Israelis will absorb the body blows of international anger. They will try to justify the killings with talk of self defence. They will continue spinning the fiction that the Israeli commandos who opened fire on the people defending themselves were actually the victims. They will talk about unproven links to al-Qaeda and will raise the menace of Iranian weapons.

But there is no doubt that last week's use of overwhelming force has left them unusually isolated.

John Ging, the UN's representative in the besieged Gaza says the Mavi Marmara killings have "exposed the failure of the international community to match its words with deeds".

The initial response has been promising. Britain's condemnation of the killings was unexpectedly trenchant, with the new foreign secretary William Hague calling for an end to the illegal blockade. The EU, as a whole, was disappointingly more muted, but still condemnatory. Turkey is now, of course, a foe rather than an ally. Ireland may be relatively powerless as a small nation, but Micheál Martin has been assiduous in describing conditions in Gaza to his European colleagues since he became the first EU foreign minister to go there. He is an articulate opponent of injustice and could argue persuasively for the suggestion by aid agency Trócaire that Israel's privileged trading position within Europe be withdrawn until the blockade is lifted. The beginnings of a change in unconditional support from the US also seem to be taking root.

The power of a people's movement lies in its ability to challenge national or international policies that are inherently unjust.

The Rachel Corrie, acting as a second wave of protest, was genuinely feared by the Israelis because of its highly-charged symbolic power. A boat loaded with humanitarian aid and carrying an Irish nobel laureate, Mairéad Maguire, and the United Nations' former deputy secretary general Denis Halliday, could not be confronted aggressively by gun-toting commandos. By all accounts, yesterday's seizure of the ship as it sailed close to the Gaza shore was a completely different operation to Monday's massacre.

But Israel cannot prevent wave after wave of similar protests. The people's movement has made enforcement of the blockade not just "unsustainable" to use Hillary Clinton's phrase, but indefensible.

These activists are showing that individuals can make a difference and that when an issue has international popular support, symbols take on a political power of their own.

While everyone cannot join a convoy, there are times when it's not enough to know that citizens of Gaza are suffering at the hands of a country that is supposed to be our friend.

A boycott of Israeli goods by Irish people may seem like gesture politics, but it could achieve two aims. It would show solidarity with the people of Gaza and it would also register collective displeasure at what the Israelis are doing.

Nelson Mandela told the Dunnes strikers, who made a great personal sacrifice during the struggle against apartheid in South Africa, that their gesture kept him going while in prison.

The activists who took part in the Free Gaza flotilla may be regarded by some as extremists, and by others as do-gooders who should mind their own business. But most of us who do nothing should remember that it is generally when injustice remains unchallenged that it persists.