That's what we all got from professor Zinn. Those who are neutral are standing with the powerful, and he said it best: You Can't be Neutral on a Moving Train.
Here is how he described his own approach to teaching:
From the start, my teaching was infused with my own history. I would try to be fair to other points of view, but I wanted more than 'objectivity'; I wanted students to leave my classes not just better informed, but more prepared to relinquish the safety of silence, more prepared to speak up, to act against injustice wherever they saw it. This, of course, was a recipe for trouble.
To that, I can only say Amen, and thank you, professor Zinn!