If you can manage to keep from lashing out (which would be very hard to do, I would imagine, but you always want to try to avoid burning any bridges if you can help it), I think this would be a great opportunity for you to explain to them why you are pulling your child out of their school and, in the process, educate them a bit about giftedness and the related issues that pertain to your son. Honestly, they will probably still think that they did nothing wrong and that your DS is "pulling the wool" over your eyes about his distress at school. But maybe, just maybe, they may care enough to hear what you have to say in a non-charged environment.
I would wait to give them the letter, though, at least until your DS is pulled out so that they don't retaliate in any way or say something to your DS that is not appropriate or helpful.
Good luck with homeschooling. I hope it works out much better for him!
