All that fighting can be blamed on this stuff:
Grass.
Sure, it looks innocent enough now, but it's caused a horrible amount of bloodshed for some 12,000-14,000 years. While wandering through what is now the Middle East, some of our ancestors discovered that the seeds that grew on the grass that was abundant in that area were a lot easier to eat if you soaked them. Plus, if you left the water they soaked in for a short while in the sun and then drank it, you would get pleasantly lightheaded, your inhibitions would fade, and then you'd keep drinking until you slept with someone unsuitable.
They had simultaneously discovered grain, grain alcohol, and the drunken fling. For reasons that may be connected to these discoveries, their population started to rise quite sharply.
After this moment, the discoveries came very quickly: agriculture first, along with settlement, then the domestication of dogs and goats, then the notion of "land ownership", swiftly followed by the invention of guard dogs. For some reason, they decided to call this "civilisation", a decision that was clearly made after too much grain alcohol.
You can see where this is heading. Meanwhile, however, the climate continued to change, because that's what it does, and the crescent of land that was so fertile they called it the "fertile crescent" got hotter and drier and less lawn-friendly. The vast grainbelts of what are now the Sahara and the Middle East shrank back.
Anyway, to cut a long story short, that's how the Levant - a very small, dusty, rocky area with precious little fertile land and fresh water - became the birthplace of civilisation, the city, agriculture, three global religions, and umpteen less successful faiths. You can't triple-book a major religious venue like that without the groupies getting violent.
In terms of human blood, the Middle East is the most expensive real estate in the world. Civilisation began there and may well end there. Regardless of the outcome of this present crisis, the Middle East will continue to be violent for the rest of our lives.
That's unless a miracle happens. And the Middle East is miracle central.