Howard Zinn is a radical, a Marxist historian whose works seek to undermine America. He has made it clear in academic writings, that he views the propagation of his ideology as more important than historical accuracy.
He is the enemy.
Zinn is one of those people we honored yesterday in all our parades. Thanks to him and people like him the last group who wanted to destroy our freedoms - Hitler and his crew - were thoroughly crushed. Zinn is not the enemy. We just disagree with him - strongly.