And in my mind, Islam is evil. One of the reasons it was able to get going, however, was that it took Jewish ritual practice and adherence to a law that governed both religious and social behavior, and combined it with Christian proseltysing. However, it was a parody of both, using an insane, run-amok, mongrel "law" in place of the genuine Law of Moses, and bloody conquest in place of the Christian preaching and martyrdom (of the preachers, not of innocent bystanders) that spread Christianity.
In addition, its message was not to turn the other cheek and conquer by being gentle and law-abiding, but to attack and collect booty and slaves, because Allah was on your side and blood should flow if people didn't agree.
That's why it appeals to our prison population: it tells the weak and dysfunctional that they are strong and meant to be in charge, not because they are good or smart, but simply because they are more ruthless. And it tells them that their reward will be all the "things" they have ever wanted: riches and sex.
Islam arose at a time and in an area where Christianity had been severely weakened by Arianism (which was a quasi-Unitarianism that made it very easy for heresy-influenced Christians to accept Islam) and the Church had lost much of its control. The Jews had fled long before, although there were many colonies still living in the area; however, they were powerless. And the Roman Empire and its few remaining vestiges of order and authority had been gone for some time, permitting little warring tribes to seize power throughout the area.
But the long and short of it is that Islam is evil, and the Devil like a roaring lion goes about seeking whom he may devour. Islam has been knocked back several times, but not without effort. But in our modern, naive society, where Christian orthodoxy is weakened, Europe has almost vanished, and the United States itself is undermined by doubt, the Devil (aka Islam) finds a lot to devour.