I'm going to give you an example and use some analogies and hopefully you can translate it to your kids or players. A long, long time ago, there was an official making some questionable calls against my daughter and she challenged his decisions in her own way which resulted in a tech. A college coach happened to be there and said, "she's a good player but she has a bad attitude and she'll never make it", well she was around 11 or 12 and we all know how that turned out.
Over the weekend, I saw a young player get upset and was ejected from a game after her second tech and then I saw an opposing player receive a tech a few minutes later. Why? For taunting the player who had just got thrown out.
My take is this, sometimes you can have a certain passion for the game and your emotions will take over resulting into being placed in bad situations, like being thrown out which hurts not only the player but the team. To me, especially when you're young, I truly understand however everyone is not me and you want to try and make your players understand that