Probably they should have, yes. Everyone has unconscious biases, and some about race in particular. That means everyone is a little bit racist. You can self monitor and try to be aware of when it is influencing your actions, but no one does that perfectly.

We can't prosecute people as criminal every time we behave like a flawed person. We would all be in jail.

To be clear, I'm speaking about your implication that every offense should be prosecuted. I'm on board with this one, it's egregious, she was leaning in to actively attack someone for their race and she was fully aware of what she was doing.