Good response Coach Brown. A red card carries such a stigma of "bad notions" -- something you don't associate with a 15-yard "Personal Foul" in football or a "Flagrant Foul" in basketball that results in two free throws and automatic possession of the basketball.
Sounds to me like someone needs to enlighten this "Principal" about soccer -- rules and etiquette. If a red card is issued to a player that pulls down an opponent on a break-away -- that's part of the game (and no punishment should be warranted off the pitch).
However, if the red card is issued because of foul language or poor sportsmanship, then that problem needs to be addressed by the coach, parent(s), and school administrators. I witnessed a match in Columbia recently that left me in disbelief of how a player was not red carded because of his/her foul mouth and blatant disrespect of an official. Even more amazing was the nonchalant attitude of his/her coaches after coming off the field. That left me shaking my head!