What? The Koran is pretty much just violence and justification for more violence: http://www.thereligionofpeace.com/quran/023-violence.htm
There is no "Blessed are the peacemakers" in Islam.
The Qur'an has all manner of contradictory messages, which can be and are interpreted in different ways. Also, the Qur'an is not the entirety of Islam; there is far more relevant material as well as centuries of legal discourse amongst ulema. Most Muslims know only bits and pieces of this, and many interpret it peacefully, and hence most of the world's Muslims aren't killing anybody.
Try actually talking to some, or getting analysis from actual scholars and not propaganda sites with blatant agendas.