I can agree with much of that. If a school has a written policy already in place that says you will face repercussions for not acting like a Lady or a Gentleman, I'm fine with that. Respect though, is a murky area. Some people will feel disrespected no matter what you do. They don't get to decide FOR ME, what respect is and is not. I'm also not a school kid.
This sounded less like that and more like political/social censorship.
As far as the 1st amendment, I believe that other people's kids have the same right to it as the rest of us. Mine, on the other hand, do not. They also are raised to understand when they should STFU, and when they should speak up. Neither would have acted poorly in this situation, imo. If they did, I would expect to hear about it.