Sorry if I wasn't clear enough about that. I didn't mean to cite Zinn as objective. I meant to cite him as a counter-example to the suggestion that US historians might be dominated by one particular set of biases. I tried to indicate this by saying, "it does suggest the biases will run in enough different directions to prevent the entire history profession from converging on nonsense."

(EDIT: tried to tweak the wording to make this clearer.)