<p>Speaking as someone who was kicked out of the school debate club by teachers who then lied about the incident to the rest of the club and the principal…
Opie’s been making some very sensible posts in my opinion and I don’t see any malice in them. No need to automatically assume bringing up another viewpoint is a personal attack 
I think it’s reasonable for any sort of educator at that level to be frustrated with someone who could work harder but coasts. Personally, I often wish I had someone nagging me in my earlier years to put in the work rather than just knowing I would get through it easily (which is why I’m here procrastinating on the internet rather than working on my essay due in next week!). </p>
<p>To the issue at hand though, I would also say it’s not a good example to the rest of the team, who perhaps can’t win debate with no preparation. Perhaps that was a consideration? What I would be inclined to do is politely enquire as to the coach’s reasoning for the decision, and explain your kid’s point of view, for example mentioning that your kid feels that others are getting away with things while he is being punished. The coach may have good reasoning that your kid is not privy to and calm discussion should hopefully avoid the notorious teachers’ united front! If you’re not satisfied with the results of that, I would then take it to the principal.</p>