In The Spectator blogs, Douglas Murray contrasts the Catholic Church's renunciation of anti-Semitic teachings to their persistence in the Islamic tradition:

One way of reacting to the problem of Islamist violence and Islamic anti-Semitism in particular is to pretend it is not there. This has been the attitude of many comfortable people in recent years. Another, equally common, position is to acknowledge it is there but attribute it solely to causes other than those which the perpetrators cite (poverty, foreign policy etc). Another is to acknowledge the religious claims which the terrorists cite but claim that they are completely wrong in this claim, that their ideas come from nowhere and could not have anything to do with Islam which is characterised wholly by its (undeniably also existent) peaceful elements. It is an understandable attitude, and, I must say, a popular one. It is bolstered by physical fear and a concern — which I now recognise is more understandable than I always have in the past — that discussions of historical actors, however truthful, may appear to be perceived as an attack on ordinary people just getting on with their lives.

Nevertheless the point has to be made. The actions of Al-Qaeda, Hezbollah, Islamic Jihad, Hamas, the Revolutionary government in Iran are obviously not a good interpretation of Islam. They are also demonstrably not an interpretation followed by most Muslims today. But they do not come from nowhere.