To clarify, my intention wasn't to say that the criticism wasn't warranted, just that it wasn't the right way to phrase it as a letter to the people involved. In a blog post directed to a general audience, it wouldn't come off as harshly, but if I imagine the principal of this school opening it and reading it... it's a different story.

And maybe I read it wrong and you weren't actually sending this letter and that was just a stylistic choice, but my impression was that you had actually sent (or were planning to send) this letter to the people involved, and that's where I say kudos on actually doing something about it instead of just reading about it as most people will do; I just want to try to increase the chances of them responding how we would hope they would respond.

Finally, thank you for the reply and for receiving my comment in the spirit in which it was intended.