I worked in government for many years and I learned one thing:  All of your written communication is public record.  My supervisor's advice was "don't put anything in writing you wouldn't want on the front page of the Register Guard."  I am quite sure that advice similar to this is given to public school employees.  Your salaries are paid for by our tax dollars - we are your bosses.  Including the parents of the girl you called fat and the girl you called a coke user.  So yeah, you should be fired.