I thought Islamists, both Shia and Sunni hated all music except the Islamic call to prayer?
Why would you think this?
There are countless massively popular Arabic pop stars whose music gets airplay on radio stations and video channels throughout the region.
Off the top of my head, Lebanon's Nancy Ajram is pretty good.
Incorrect. There is a lot of Islamic music—especially from Iran, which has a very rich musical tradition. Much of the traditional Greek music was influenced by the Ottoman Empire when Greece was under Ottoman control for many years.