I agree with you about the social media harassment of the young woman.

But. The school had the right to do it, as long as it was spelled out in any documentation on school discipline practices.
I consider the school to be acting sanctimoniously, but they're within their rights.

As far as I'm concerned, this is exactly how some pro-life Christians behave. Preach against abortion, and then make the pregnant woman an object of scorn.