I don't think it's the Koran that is the problem, it is that a lot of the Middle East which practices Islam is living in undeveloped conditions, and so Islam is the only reality a lot of people know. This is especially true in the very rural and outlying areas. The Bible is full of violence and hate too if you wish to hone in on those specific passages, but as most Christians will tell you, people don't cling to so many Old Testament notions anymore, and that is entirely because most Christians now live in modernized, free nations, with access to higher education, where they know that it's not okay to smite people for not resting on the Sabbath. The way religion is perceived and is used evolves alongside everything else.
If you go to India, the cities are becoming more and more modernized, which means more education; but if you go to the rural countryside there are still people who believe in superstitions stemming from Hinduism about pleasing the gods or else death. (Just FYI, I'm not making any assertions about the validity of their faith, just the politics.) Even the urban people talk about how backward the countryside can be, and they live in the same nation.
To say that the root of violence is Islam is to deny all the other factors related to the violence, like politics, corrupt governments, economy, lack of stable development, war, poor access to education, regional security, etc. All of these things affect what values people are taught growing up. Afghanistan for example was a thriving proto-democracy before the British Empire, and the USSR and American campaigns of the Cold War; it had a rich culture with the foundations of civil rights beginning to form. Then it got torn to hell by war and politics, and as usual the tribal leaders and all their values seized control of the nation. The Taliban does not represent the best of what Afghanistan can achieve, and its radical Muslims do not represent the kind of society that was there before it became so war torn. I wish more people would learn the history of Afghanistan to see how cool it was even less than a century ago.
A lot of people are lacking the insight into the bigger picture of the Islamic world, especially from an historical perspective. Yes there has been barbarity, and yes the Koran has violent passages, but the choice over what passages get used in the world has always been determined by power politics. It is really easy and tempting to blame Islam for everything but usually it's corruption and under-development of nations that causes people to turn to religion for the solution to everything.
