There is no religion as confusing as Islam.
Islam, as it is followed by the vast majority of moderate Muslims, must surely be the real Islam. You cannot imagine that the majority is wrong.
But consider the case of the so-called Islamists: the fundamentalists, the radicals, the extremists, the terrorists, the followers of “political Islam”... in other words, those who follow the “extreme” or “literal” interpretation of Islam. It now appears that these Islamists often come from Quranic schools, and have studied Islam thoroughly. Even Muslims living in Western countries follow Quranic courses before going to fight in Iraq.
The moderate Muslims, even those with a good education, generally have a limited knowledge of the Quran. They know a few verses here and there without knowing the context. And it seems that they all share the same small collection of verses saying Islam is peaceful.
The confusion is complete. The more you study the Quran and Hadith the worse it gets. With the so-called "Islamists" there is a familiar pattern: at a certain moment in their lives they become very religious, they decide to dedicate themselves to Islam, and then, without fail, they totally “misunderstand” what Islam means, by planning or committing terrorist attacks, for instance.