A great quote from another site:
"If any of you have actually read koran, you will know - it is not only a religious text, intending to govern inner space of an individual. It is a fully laden constitution, complete with civil and criminal law. Everything, ranging from how to distribute inheritance to what 'rights' minorities can have in an islamic society, is tied to concrete rules there. Curiously, most of the rules contained therein are similar with hedjaz tribal customs and laws (particularly quraish tribe) from pro mohammad times.
However, because koran is the 'unchanged' word of god (so says islam), it is unobjectionable. Add to that the fact that islam based on koran is put forth as the only way to live for muslims in koran, it makes islam impossible to coexist with any other social system or law. This is the cause of the friction in countries that are not from middle east, have modern legislations, and muslim minorities.
Egyptian reformers tried to deal with these, tried to 'modernize' islam, and 'reinterpret' koran in the light of modern principles. Results were disastrous. Some of them were killed, some of them had to flee the country, and some of them had to shut up. The struggle continues even to this day. Because koran is put forth as unchanged word of god, it is impossible to find any excuse to reinterpret it. And because you cant reinterpret it, you cant make it compatible with modern principles and views.
And this creates the basis of power for islamism, ie the noticeable segment of muslim organizations that intend to create a one world sharia government. It is impossible to argue against them, because of the above issues.
Ironically, muslims also suffer oppression from this, because the direct interpretation of koran, well, comes up medieval. If you attempt to fully adhere to islam, numerous civil oppressions become inevitable, due to the rulings set in koran. However, mild muslims, a noticeable percentage of muslim population around the world, also cant argue against this, because it is set in koran, and koran is unchanged word of god.
Until these issues are solved, islam will be creating problems and not be able to fit in."