Bruce Thornton says it like it is:
Islam does have a theology of violence attested in numerous scriptures from the Koran, as well as in the collection of Mohammed’s deeds and sayings called the Hadith, and in fourteen centuries of Islamic jurisprudence and theology. This injunction to “slay the idolaters wherever you find them, and take them captives and besiege them and lie in wait for them in every ambush,” as one Koranic verse has it, clearly does not refer to some Dale Carnegie-like course of self-improvement, or to a mere spiritual struggle. One of Shiite Islam’s most revered figures, the Ayatollah Khomeini, certainly didn’t see it that way: “Those who know nothing of Islam pretend that Islam counsels against war. Those [who say this] are witless. Islam says: Kill all the unbelievers just as they would kill you all!” So too Hassan al-Banna, founder of the Muslim Brothers that many now believe are “reformers” struggling for liberal democratic freedom in Egypt: “Fighting the unbelievers involves all possible efforts that are necessary to dismantle the power of the enemies of Islam including beating them, plundering their wealth, destroying their places of worship, and smashing their idols.”
It's stunning that after fourteen hundred years of aggression, some still call this blood-soaked religion peaceful!