There are four reasons for this.

First, Islam is marked with a history of violence, including a thousand-year struggle with the West. (And yes, Christians have also participated in religiously motivated violence; when they do so, however, it is against what is professed to be their belief. This is not the case with Islamic violence, which is consistent with the Quran.)

The Second reason is the Quran itself. I have read enough of it to be satisfied that it does call for violence in a number of areas.

The third reason is that Islam does not respect pluralism. It is a theocratic religion. Like any other autocratic regime, a theocracy will use violence if necessary to suppress dissent -- and then some.

The fourth reason is a particularly virulent strain of Islamic radicalism known as Islamo-fascism. It is largely motivated by the writings of Said Qutb, an Egyptian radical, who was executed in 1966. His books, including In the Shade of the Quran, have become handbooks for the Muslim Brotherhood and many of the violent extremes of Islam. Even a cursory reading of his work could convince anyone that he was a fascist -- and it is historically so that he was hugely influenced by an anti-Semitic German intellectuals who also influenced Hitler.

In the light of this, is peace possible? As a Christian I believe we should be constantly working for peace and hoping for peace in order to further the spread freedom and democracy, not the spread of theocracy.