(Double) standards of proof

After a couple of careful paragraphs condemning terrorism and stating that a justification can be “to the wrong-headed, compelling” while still being “spurious”, the Guardian gives us this:

Can it be denied that the invasion encouraged a growth in al-Qaida's threat and influence?
… That techniques from Iraq - petrol and gas canisters placed in cars - seem to have been exported to the UK is more than symbolic. It is not proof of a direct link with al-Qaida, nor should it absolve the would-be bombers from condemnation. Yet it is wrong to claim there is no link to Iraq.

Are you clear about that? It’s really too soon to tell whether the failed London and Glasgow bombings had any link to al-Qaeda. But we can say with certainty and without hesitation that these attempts to kill clubbers in Soho and Scottish families going on holiday were, at least partly, because of Iraq (which, by a staggering coincidence, is one of the Guardian’s favourite bugbears).

Someone who knows whereof he speaks is Hassan Butt (ex-member of al-Muhajiroun):

I remember how we used to laugh in celebration whenever people on TV proclaimed that the sole cause for Islamic acts of terror like 9/11, the Madrid bombings and 7/7 was Western foreign policy.
By blaming the government for our actions, those who pushed the 'Blair's bombs' line did our propaganda work for us. More important, they also helped to draw away any critical examination from the real engine of our violence: Islamic theology.
…what drove me and many of my peers to plot acts of extreme terror within Britain, our own homeland and abroad, was a sense that we were fighting for the creation of a revolutionary state that would eventually bring Islamic justice to the world.

And also Ed Husain, another onetime jihad cheerleader:

Just as the IRA bombed and maimed, and Sinn Fein explained the motivations for mass murder, jihadists today plant car bombs and dispatch suicide bombers, while entryist Islamists from the Muslim Council of Britain and a host of other organisations explain their “legitimate grievances” to us. But unlike Sinn Fein’s demands, Islamist calls for the annihilation of Israel, overthrow of all Arab leaders, and changes in western culture cannot, and should not, be met.
The tone of British Muslim communal discourse in relation to national security and terrorism is worrying. Among young Muslims, there is a widespread Islamism-influenced belief in a bipolar world: a lethal them-and-us mentality. The police and intelligence services belong firmly to the “them” side of the divide. As do clubbers, Jews, gay people, Christians, atheists and even moderate Muslims who reject the extremists’ war call.