Islamic/Muslim Law

It’s amazingly interesting to me to see how the governments of Afganistan and Iraq are panning out. As Americans, we tend to believe that Islamic law is prohibitive, works against human rights, etc, etc and it would “obviously” be in the best interest of nations we’re taking over (ahem, I mean, liberating) to instill a law perhaps like our own. So then why is it, so often, that people rally in support of Muslim law and having their legal system rooted in the Quran? One good example I saw of this was this article on Al Jazeera, where one group of women wants to have the Islam matrimonal tradition and another wanted to keep an Iraqi family law that prohibited polyagamy. The more and more one read in the news and otherwise makes it clear that our Americain/British legal system is not appropriate or adaptable for Middle Eastern cultures.