It's that 7th Century mindset mandated by their religion. It precludes their development as a society.
Not just Zombies, but stupid cops too...
Then lets take them back another 2000 years.
It's not like they'd notice.
The problem with that mindset is that it only applies to things they want it to. They want to force all Muslims (as well as Westerners) into a 700 AD culture, leaving behind modern technologies, but they are using modern technologies (cell-phone triggered bombs, car bombs, etc.)to force people into siding with them.
They see no problem with this thinking, though it's not a logical approach, by any stretch of the imagination.