Kids don't run up the points in a match to humiliate their opponent. They do it for various reasons which are valid and reasonable.
1. No kid wants to go to a tournament all day, and step on the mat for less than 1 minute (the winning and/or losing opponent).
2. The practice room is not the only place to practice and get better.
3.There are going to be times in a wrestlers career where he is going to have opponents he cant pin. Therefore, cutting them, and taking them down, securing near fall if he is able to and running up/increasing the lead will be necessary to obtain a major or tech. Tournaments and duals are perfect opportunities to work on this.
4.If an wrestler pins his opponents within the first period every tournament, when he faces a tougher opponents and has to go the distance, he may struggle in those matches if he hasn't placed him/herself in those positions in the competition environment.
5.It is not disrespectful to beat your opponent by technical superiority. If a wrestler shakes hands, is kind and respectful, showcases his/her skills, and walks off the mat without being loud and inappropriate, then he/she is certainly being respectful.

As a coach or parent, if you cant handle your wrestler being shut out and/or handled with technical superiority, then you have a lot of maturing to do . You can't win every match. Some matches are going to be close Some matches are going to be a blow out. Teach your wrestler to take his losses and get back up. Use the big losses as motivation to get better, watch your tapes, make changes, put in more mat time and aim for getting 1% better every tournament, every practice, and every dual.