All because this cretin was black? The fact is blacks are the privileged ones here; they have grown to feel entitled to say and do anything they want - simply because they are black - the government, the media and the ACLU are their stalwarts. This teacher is evidence of that.
Yes, the background of the assignment, which I suspect was minimal. The nature of the teacher's past lessions. She's not rewriting history, though imo she's approaching in from the wrong perspective. But I'd have to know more to fire her or remove her from the classroom. Which I suspect the school does.