Wow there is no way I would ever subject my kid to this kind of hostility. You keep trying to pinpoint one person here. IT seems as if the coach and staff have targeted someone's kid.
Is it some kind of scare tactic to stop talking? Is this how you coach? By intimidating kids? Look at every post. It's not sour grapes. Then look at other forums. It's a common theme.
There is no way you can positively identify an anonymous post. In order to that with certainty, you would need a court order from the supreme court. There are privacy laws regarding anonymity. So in essence you are making the PT staff look like they are targeting one parent here when in reality you have no way of knowing for sure. It really looks bad.