Art is art, whatever the religious beliefs of those who are making the art may be. I know little about Islamic music, but there is beauty in the designs of the mosques, and in the elaborate prints and motifs found in tile works and in the hand-made copies of the Koran. I've seen such items at museum exhibits celebrating Detroit's arab americans.
American pop culture, at it's best, has elements of the religious beliefs and the cultural experiences of the people living in our nation. It is wrong for someone to purposely try to keep kids from exposure to music based on religion-as wrong as it is for a christian to tell a kid that isn't his kid that he can't listen to music that isn't christian in nature.
And, if kids are actually studying music history in school, how could a teacher avoid talking about music with religious roots? The histories of rock, country and jazz have elements of the southern christian gospel music tradition interlaced in their histories. Classical music has much of it's foundation in the european catholic mass tradition. Some composers' most moving music is the work they composed for the celebration of mass.
I'm a liberal, I don't think there should be organized prayer in public school, but students are free to express their beliefs in an appropriate manner. If a teacher asks the class to write a paper about what the students did that summer, and a kid turns in a paper about finding Jesus at summer camp, the paper should be graded on it's merits, and the kid shouldn't be told it's not appropriate for the assignment. If a teacher asks students to write papers on the most important thing in their lives, that teacher better be prepared for some papers to be written with religious themes. The issue with schools shouldn't be about the expression of one's religious beliefs, it should be about preventing any group from forcing their beliefs on another, and about the school refraining from sponsoring or endorsing a specific religion.