Earlier quoted context omitted.
This case would be argued along exactly the same lines before the court had the student in question thrown in a racial slur. It will also have an impact on the ability for schools to punish students for racist cyberbullying in future. So I don't think it's problematic in the slightest to bring race into the equation.
One is criticism of the running and operation of an organisation; the other is steeped in the history of genocide and slavery, there are even laws in place around the world to protect people from it because of it's heinousness. But you're professing that advocacy of racism is no more malignant than basic complaints about a company? I'm not sure if what you're advocating is because of perhaps missing education on the…
If the Supreme Court made an exceptionally broad ruling to the effect of forbidding any organ of the state revoking an appointment on the basis of first amendment protected speech uttered while not performing duties, then the ruling would protect a racist police officer and irate cheerleader equally.
The Supreme Court is, of course, very unlikely to make such a broad ruling in this case, but it does seem like that's the remedy which quite a few people in this thread would like to see decided.