Let’s be honest–nobody is mad at Karega because of any of that–they are mad at her because of her viewpoint and her expression of it. It has little to do with her ability to teach rhetoric. If she had posted her opinion that the pyramids were built by space aliens, that fluoridation of water saps our vital bodily essences, and there really are fairies and elves in the back garden, nobody would be calling for her to be fired (even if they thought she was a nut).
Is there any evidence that her offensive views were communicated in the classroom, or that she taught anything that was not factual in the classroom? If there isn’t, she’s no different from the electrical engineering prof with horrible beliefs who doesn’t address them in the classroom.
Let me just repeat that Oberlin, as a private institution, can fire her for her views. But a public university would have a much harder time overcoming her First Amendment protections.
Note: here’s an interesting article about the example of shouting “fire” in a crowded theater, and how it can be misused: http://www.theatlantic.com/national/archive/2012/11/its-time-to-stop-using-the-fire-in-a-crowded-theater-quote/264449/