This whole passionate issue  of "firing people" is ridiculous.  -It's not going to happen.  A senior, tenured law professor can be fired about as easily as a bicycle can tow a truck.  Some of those who signed the petition may be tenured as well and they're not going to be fired for a legal act.

As to what the law professor's actual motivation was, I don't know and won't rush to judgement  til I see the results of the investigation.  Her public "apology" was questionable, as she refused to acknowledge the social nature of her act-- she studiously avoided any reference to "Blackface", admitting  only to using some "black makeup."  She also seems to believe that she is perfect and can do no wrong, as she was shocked that "I, of all people" could be accused of lack of sensitivity.
But these are certainly not "firing offenses", and I'd urge that we all calm down until we actually know more about what did happen.  And then we need to patch up the bad feelings this event has caused.