Is there a connection? The murderer of Theo van Gogh was a sexual failure in Holland. Mohammed Atta went to a strip club before 9/11. The sexual repression in much of the Arab-Muslim world means a lot of frustrated young men, eager for some kind of escape. Ian Buruma has a typically fecund essay on the topic here. Money quote:

"Sexual deprivation may be a factor in the current wave of suicidal violence, unleashed by the Palestinian cause as well as revolutionary Islamism. The tantalising prospect of having one's pick of the loveliest virgins in paradise is deliberately dangled in front of young men trained for violent death. And even those who are not trained to kill and die often live in authoritarian societies in which sex before marriage is strictly forbidden, in which women outside the family home are not only supposed to be untouchable, but invisible. Access to MTV, the internet, DVDs and global advertising reinforces the notion that westerners live in a degenerate garden of sinful delights. This makes the lot of millions of young Arab men even harder to bear, and can provoke a mixture of rage and envy."

I cannot believe that a culture in which half of humanity is essentially in slavery to the other half, and in which all sexuality is treated as potentially damning, is a culture at peace with itself or the world.