each of us would have different opinions and approaches to the same scenario, so ultimately you will need to do what you feel is best within your constraints. Punishment for this is not really going to address the root problem. What do you want him to get out of school? I think you need to answer that question - what is important about your son going to school - and this particular school - now? Down the road? what benefit will you get by letting him do gymnastics? not doing gymnastics?
quite frankly - it sounds like a really, really bad fit - either with the teacher or with the school. if it were me, I would be yanking my child out and figuring out either another school or homeschool. But I also live in a state that is not difficult to homeschool and I have the resources to know I can do this. And I am more inclined to just say "screw it, we are done with you, good bye" than try to fight what looks like a long, painful battle that won't net me much gain but may lose too much time in a toxic environment. We know kids grow up fast, and the sooner you address this apathy to school - and learning - and at a younger age, in my mind, the better the long term prognosis for the person in question will be.
