The First Amendment protects everyone's right to say what they have to say without the fear of any consequence. After all, everyone has to abide by the amendments of this country.
Doniger vs Niehoff was a court case that involved Ms. Avery Doniger suing her principal for removing her from the senior class secretary race because Doniger called her "a douchebag"
This court case was a back and forth between the student and principal, even involving Doniger bringing up the Thomas v. Board of Education case. In the end, however, Doniger took the loss in the case.
Personally, I don't think that the school should've had a rule that allows off-campus statements become punishments. Doniger was just really upset and she had the right to say what she wanted to. This case shows that younger people's freedom of speech is beginning to slowly deteriorate under the rule of their teachers and other school officials.