Your assumptions are completely ridiculous. Voluntarily reciting the Pledge of Alligence at school, which merely generically acknowledges the existence of a God, does not establish a state religion. Refusing to allow students the right to recite the Pledge of Alligance in school would be violating their free speech rights. Why do you believe that a student's free speech rights are not legitimate within the setting of school walls?
Refusing the right of students to acknowledge the existence of a God in school and the honor of pledging their loyalty to God and country, would be a prime example of government being an adversary of religion and religious expression.
By the way, you forget to mention the Free Exercise Clause in your quote.
Man, you just can't help yourself, can you? Where have I ever said I was against voluntary recitation? Where did I ever state that such 'establish[ed] a state religion'? Where have I ever advocated refusing to allow (allow, not force) recitation (therefore rendering your next assumption all the more ludicrous)?