It would be very easy to blame our current troubles on Islam, and many have. But Islam was in no small part created as a belief system to break the virulent, violent culture of the Bedouin. At heart Islam is a gentle, extremely rational belief system. It's full of admonitions along the lines of "pray 5 times every day, but if you can't pray 5 times every day, that's OK, God understands, give a little more money to the poor", and "fast during Ramadan. But if you can't fast, that's OK, God understands, give a little more money to the poor".
What we're doing is mistaking religion for culture. Pretty much all modern religions proscribe a belief system that, if followed with a true heart, fly in the face of behaviors deeply engrained into the chimpanzee in all of us. It works at first because the community is small and there's a leader with enough charisma, intelligence, and passion to hold it all together. It starts to fall apart because the community gets bigger and the prophet ends up dead.
The thing that differentiates a cult from a religion is the way it handles its believers. Without exception, the core of a true religion tries to get its believers to think about its beliefs, challenge them, test them, and through the testing faith will be found. Cults gauge success only by the number of bended knees that can be counted.
But finding faith this way is hard, harder than any other thing an individual can do for themselves. It's so hard that huge numbers of people, across all cultures, simply never attempt it. The unfortunate fact is it's all too easy to think your life is hard enough without having to challenge the comforting hatreds and habits you grew up with. My brother once said army basic training convinced him the human body can do amazing things when the mind allows it. I just wish people would understand the human soul works in the same way. Believing what the preacher tells you just because he's the preacher is not what Jesus wanted.
So what always happens, especially with the religions "of the book", is the culture ends up controlling the movement. And the culture of the Middle East was one that demanded unquestioning loyalty to the tribe, reacted to the slightest threat with overwhelming force, never ever forgot an insult, and encouraged acts of personal violence as a method of political advancement. Arabs were like this for thousands of years before Mohammed, and they would be like this for more than a thousand years after.
Arab culture wasn't just about these things of course, but I would argue strongly that the good parts of Arab culture, the ones we should all rightly cherish all over the world, were given to it in no small part through the Koran, and the Koran was written in no small part as an attempt to overthrow the dominant cultures of the time.
But unfortunately there was just one prophet and millions of lazy, too-accepting believers, and once the prophet died the society used the movement as a vector to spread the violent culture of its birth.
"Ah ha!" you might say, "Christianity came from nearly the same place, and it's not known for the same level of terrorism!" Notwithstanding the wacknuts living in America's heartland and the memorial in Oklahoma City, this would at first seem a valid point. However, it must always be remembered that while the Jesus movement got its start in the Levant, Christianity is primarily a Roman invention. The two core branches of Christianity, Catholic and Orthodox, both were set up, survived, and thrived under the aegis of the emperors of Rome.
And, as with Arabs and Islam, the culture of Rome hijacked the Kingdom of God and used it to spread its beliefs. Male dominance, absolute loyalty to doctrine, subservience to hierarchy, and the abject inferiority of women, none of which, not a single one, can be found in anything Jesus actually said, are now deeply engrained beliefs far beyond the borders of Rome in both space and time.
It's not the belief systems that are causing the problems. It's the people. Powerful men are perverting a beautiful doctrine of justice and peace not to bring liberty to a downtrodden people, but to gather more power to themselves. Weak people are allowing this to happen by believing instead of thinking, allowing rage to dictate their religion, and trusting the words of men instead of reading the words of God.
It has ever been thus. The physical spawned the spiritual, and the spiritual spawned the intellectual. Science has proven to be the key to human liberty, but science is intellect laid bare, thoughts naked and cold. Rather than see the triptych existence of body, mind, and soul, and nourish each in turn, too often the ape falls back on what it knows... that it and its kin are superior to all others, that the tribe keeps it alive, and that there is only victory or death.
The true prophets of humanity were those that chose to fight the ape, often at the cost of their lives. Each has in turn helped lift us up with their vision, challenged us to make more and better things out of our lives, taught that victory is death, and only by breaking out of our habits and deceits can we ever reach the divine.
Humanity's greatest problem isn't famine, or war, or disease, or religion, or death. It's our overwhelming, seemingly uncontrollable urge to bend our knees rather than use our heads.