La Cosa Nostra is not a religion. Islam is, albeit a sick one. The First Amendment doesn't distinguish between religions we like and ones with which we disagree.
It depends on who is interpreting the First Amendment. If the left does it, the First means no Christian prayer in school, but courses mandating students emulate muslim practices are OK. If the left interprets the First it means Christian groups, including the Boy Scouts, can't use public facilities to meet after hours, but muslim groups get to meet during the school day, and non-muslims are ordered either to attend and show respect, or shut up about it altogether.