I think it is unfair to say that Bush and Blair "helped" bring the attack. Certainly they did not wish or intend for this to happen. But I think you and the referenced commentators correctly point out that they did have a role in what happened. I think the role is not "helper" but "unwitting enabler". This attack was "predictable" for us because we can think through the consequences of violence having observed them and having learned them through study of human history. We have seen over and over that violence, as it is being used by the various players in Iraq, and in terrorist bombings such as those in Madrid and London, will never be the answer. This type of violence will only be met in answer with still greater violence. Dr. King captured this truth so well in the quote below. It is not that Bush or Blair "helped" it is that they have not fully realized this truth:

The ultimate weakness of violence is that it is a descending spiral, begetting the very thing it seeks to destroy. Instead of diminishing evil, it multiplies it. Through violence you may murder the liar, but you cannot murder the lie, nor establish the truth. Through violence you may murder the hater, but you do not murder hate. In fact, violence merely increases hate. So it goes. Returning violence for violence multiplies violence, adding deeper darkness to a night already devoid of stars. Darkness cannot drive out darkness: only light can do that. Hate cannot drive out hate: only love can do that. Hate multiplies hate, violence multiplies violence, and toughness multiplies toughness in a descending spiral of destruction.... The chain reaction of evil -- hate begetting hate, wars producing more wars -- must be broken, or we shall be plunged into the dark abyss of annihilation.