You do understand that in the U.S. the right of 'free speech' relates to the government and citizen relationship don't you? And, even in public schools, the Supreme Court has ruled that there is no absolute right of free speech.
I understand both of those things perfectly well.
If you're going to argue that their indefinite expulsion was not an abridgement of their 1st amendment rights (which they retain), then lets look at the justification. We can examine the bylaws and whatever contracts govern attendance.
