Islam makes the absurd claim that the Koran is the absolute literal word of god (the language god speaks, thinks and writes in), which was dictated to, but not written by, Mohammed. Unlike the Holy Bible, there is no human mediation possible in the words of the Koran. Nevertheless, once the book called the Koran is opened to historical verifiability and higher critical interrogation among true scholars and Muslim, non cult members, it cannot be substantiated as god's pure word.
Like most cults, Islam is an all-or-nothing proposition. Any fault in the Koran that was entrusted to humankind, or doubts as to the truthfulness and reliability of Mohammed (not to mention uprightness), should cause the whole system to disintegrate for all but the severely manic. Muslims already subconsciously realize this, because they fly into tantrums whenever either Mohammed or the Koran is 'disrespected'. Under Sharia law any criticism of either Mohammed or the Koran is blasphemy which is punished by death (even the NYT reports this information).
This paranoid, hypersensitive defensiveness and outrage at candid criticism are not the reactions of a confident belief system, but that of an insidious information-control cult. Reactions of this nature give clear evidences of Islam's core deficiencies. In short, they are disingenuous efforts at shielding a terminal vulnerability, an attempt to cover an Achilles heel.
The location of that Achilles heel was amply demonstrated by the Satanic Verses affair, the Motoons rage, and by the Organization of the Islamic Conference's insidious attempts to introduce global laws against 'blasphemy' of Mohammed (not to mention the recent slaughter of vulnerable Christians, Human rights advocates and defenseless office workers worldwide). In fact, the Muslims themselves have put on public display their most vulnerable and dreadful pustule, which is the questionable (though unquestioned) character of the 'Prophet' himself.
Note: The above words are highly edited annotations of an anonymous and mostly veiled human source. As I recall, the editor himself was terribly offended and deeply hurt by the recent abduction of his insubordinate, eldest son by a subversive, Islamic conspiracy cult whose goal was to kill (again, see Hebrews 6.6) the Jesus of Holy Scripture.