Ok, I've read the entire meandering thread, and while I'm not sure the OP is even reading it anymore, I'd like to present one more idea about the teacher censoring your child's talk. Censoring ourselves to know what is appropriate or not appropriate to say within specific groups is a vital behavior skill that will help our children be successful in the workplace, at home, etc. there are things we discuss with our spouse, say about intimacies, that would be horrifically inappropriate to discuss with our children present. That is called discretion and does require that we censor our choice of topics because of the harm it could do to someone else witnessing the discussion. There are a myriad of examples of how we use discretion.
Your child is being given a valuable opportunity to learn how to use discretion and self control for the sake of others.
My daughter was given the same opportunity when she chose to enlighten a group of children on the playground about the facts of life at 8 years old. She'd asked questions; I knew she was advanced in her ability to process the information appropriately, so I gave her direct answers. It seems many parents were not so inclined to share the same information with their children, and thus one parent called the principal upset that they now had a child who knew things they weren't ready to process. It was a good opportunity for me to teach my child that just because she was mature and advanced didn't mean others were and that being respectful of that was an important skill to acquire.
Just a thought; hope it helps.
As to the parents signing things for a kids's grade - it's a massive pet peeve of mine, it in no way indicates anything about the kid's grasp of knowledge at all.
