The uninformed, reactionary responses here are appalling. 

Firstly - Christian prayer was abolished in schools because it was forced on all students and presented as a school sanctioned, "state" religion excluding all others.

Secondly - Muslim services are not mandatory, they are only for those students who wish to attend.

Thirdly, schools were having problems with students not attending on Friday due to it being the Muslim holy day, just as Saturday and Sunday are for other religions. Having services in the school on Friday allows for students to attend classes and services.

Fourth - consider that the school calendar is current not secular in the first place as it avoids classes on Christian holy days.

Fifth - the arguments that the students have made about freedom of religion and avoiding state interference, all entirely justified, follow the best traditions of our country and aren't all that far off of the anti-government rants often posted here by the usual reactionaries.