Your distinction between a war "just about Christianity" and a war with "heavy Christian overtones" seems to me to be a bit of rationalization. And honestly, I am not sure why it is necessary to deny the rampant violence, not to mention toxic anti-Semitism that permeated Christian history. That was then. Now, I am raising my Jewish children in an overwhelmingly Christian country and they have not known a moment of anti-Semitism in their lives. Things change.
It all depends on your perspective, I suppose. On the one hand, it is true that Islam has had 700 fewer years to "mature" than Christianity; on the other hand, as you correctly point out, we live in a more enlightened time. We also live in a more technologically advanced time, which means that Islam's violence may ultimately prove far more destructive than its predecessor religions'. Hopefully not, but we'll see.Additionally, you have to keep the time periods in mind, as they are relevant. You can't compare what happened hundreds of years ago, when freaking everyone in the world was brutal to modern times.