I would ask the Asst. Super if she realizes that most the other sports at the school also charges a camp fee. And to keep from violation of some rules I believe most people say its is for a camp T-Shirt. And that some of the other sports will in some way hold it against a student who does not find time to attend, thus almost making it manditory to play on their team. And where was the AD during this time, instead of a of a Asst. School Super ramroding the whole ordeal?
But based only on the facts we know for the reason of the termination is almost childish on the schools part. Good Luck in your quest. And I hope that the reason they used of health and safety of the students welfare, with that said it sounds no ones jobs are safe in that school.
So you could look at it like they opened better doors of opportunity for you, and in the end you will realize they done you a favor. And like earlier said, their lose, will be someone elses gain.