...surely that can't be enforceable.  You cannot have somebody sign an agreement to give up all "fair use" rights, because "fair use" rights are legal.  It's tantamount to legally taking away somebody's legal rights.  Surely that would not hold up in court.

EV's concern is that somebody will have access to the Keys and then quote from them on the Internet and criticize them.  If that happens, (and that IS going to happen),  they want to be able to sue that person.  

 No self-respecting, intelligent person will sign that agreement.