The ACLU to Religious Minorities: Cut It Out!

In a recession, the problem most people and organizations face is too little money.  But clearly, that's not the case with the ACLU, which apparently has ample time and money to sue to prevent a charter school from unconstitutionally promoting Islam.  In a way, this is very good to hear, because it makes it easy to direct my giving to organizations with more urgent needs.  On the other hand, what the hell is wrong with the leadership at the ACLU?  In theory, for all I know, it unconstitutionally promotes religion.  In practice, what important freedoms are being violated?  The establishment clause was supposed to prevent a minority from being oppressed by a majority, not to prevent a minority from oppressing itself.  I admire a huge amount of the work that the ACLU does on issues like habeas corpus and wiretapping.  Why, then, do they so often seem intent on turning the organization into the highbrow edition of Stuff White People Like?