I agree with mariabush, this has been a problem since the time of Abraham. While Islam came later, it served to galvanize the Arabs and reinforce their pre-Islamic culture. It eradicated some of the weaker factors (such as idolatry, polytheism) and brought law, unity and cohesion. It made steel out of the native iron.
As for the Holy Father apologizing---I'm only sorry he wasn't in Infallible Mode when he said it. Then nobody would ever take it back! :)
The Arabs were probably the most dysfunctional residents of the ME, surviving as wandering herders and bandits when almost everybody else was settled in cities and engaging in trade. But the more advanced ME societies - many of which were majority Christian, with heavy sprinklings of Jews, btw. - were suffering from a power void left by the fall of Rome and the weakening of Church unity as a result of the Arian and subsequent heresies. In other words, they were vulnerable, and once Mad Mo dreamed up his insane, Arab-centric syncretist cult, it was very easy for his hopped-up bandidos to overrun the cities and kingdoms around him.
I think this has always been Islam's secret: it simply launches itself aggressively, like any barbarian attack that Mohammed's tribe would have launched back in the caravan-attacking days, and more established, civilized societies are so caught off guard that they don't respond until too late. If one thinks of OBL attacking the US, for example, it's almost laughable; the only good thing Maureen Dowd ever said was that it was like waking up and finding that the US had been attacked by Fred Flintstone. But he did it, and I think the sheer primitiveness of it took us by surprise and is also perhaps one of the things that is behind the weakness and confusion of the response of many of our leaders.
I guess Mad Mo found a winning strategy.