This is true of all history, regardless of political viewpoint. There is no such thing as objective explanation of history.
Reshaping American society may be a fine goal. And, Zinn certainly has been successful at that, but it does not sound like history to me.
It's definitely undesirable to admit the concept is meaningless, then to strive for it. That's just producing propaganda. You know the standards you're going to strive for are arbitrary and just made up of a combination of things you haven't questioned the importance of and things you've decided the importance of, but not only do you cleave to them anyway, but you criticize those who deviate from them as dangerous propagandists.
He thought his job was to create a more rational, more just society, and the narrative he used to connect the events described in his sources was a servant to that. That's the same thing that people who claim objectivity claim to be doing, while they write history as the conflicts between the wealthy and royal.
Claiming "objectivity" is just claiming that someone would be insane or seditious for daring to question the claimant's premises. Claims that objectivity is real inevitably ends in journalists and writers having to be licensed and approved by the government.
Consider an event that created some gain for a country at the expense of a specific group of people. A history book that claims "This event helped the country through so and so" would be biased because it chose to include some piece of history while excluding the other. Similarly, a textbook including the latter part but not the former would also be biased.
Now you may argue that including both consequences of the event would make the textbook unbiased but it actually suffers from the same problem. The very inclusion of any one piece of history is biased because you're making an explicit decision to include some event but not everything else.
I agree with you that we can and should strive to be more objective, while accepting that true objectivity is not possible. However, it's important to understand that at the time of Zinn's writings, history was heavily biased towards one end of the spectrum. The intention of his own biased history was not to balance the scale, but to introduce the overlooked and erased aspects of history into the conversation.
Zinn was basically saying "Look, we can't fit every little aspect of history into what we teach our kids. So if we're going to pick and choose the narratives and lessons that go in their books, we need to choose the ones that will help us avoid the mistakes of the past and shape a more just society. If history is going to influence the world, it should be for the better".
Of course, but that shouldn't be an argument to completely dismiss attempts to be less biased.
You achieve lesser bias by constantly doubting and questioning your priors.
You establish authority and trust by actively communicating to your reader or interlocutor legitimate doubts people should have of even the position you're offering. There is no greater smell that you should be concerned about someone's biases than when they present nothing but certainty and when they craft arguments that deliberately elide contradictory or exculpatory evidence.
I agree, and I explicitly took this position in my initial reply.
> You achieve lesser bias by constantly doubting and questioning your priors.
This is what Zinn was trying to achieve by introducing the parts of history that don't make it into the textbooks.
> You establish authority and trust by actively communicating to your reader or interlocutor legitimate doubts people should have of even the position you're offering.
I'm not a Zinn or a history expert by any means so this is a bit above my pay grade. All I can say is that from some of Zinn's essays I've read, one of his main points was that you need to be critical of the history you're exposed to and try to understand what the text is trying to accomplish. In Zinn's texts he makes what he's trying to accomplish very clear.
> There is no greater smell that you should be concerned about someone's biases than when they present nothing but certainty and when they craft arguments that deliberately elide contradictory or exculpatory evidence.
You're absolutely right. This was the major idea Zinn introduced to history in academia.
It honestly seems to me like you agree with the central thesis of Zinn's writings. A lot of the criticism I've been reading in this post mirrors the same criticism Zinn had of academic history when he first began writing.
I mean, his autobiography is titled "You Can't Be Neutral on a Moving Train", so I had the impression that Zinn cautioned against attempts at objectivity/neutrality because it often serves the status quo, and actually hides the truth, not because "he believes he serves a higher value than truth," as you say.
At a high level, this seems pretty uncontroversial to me, blind pursuit of "objectivity/neutrality" is not uncommon, and often leads to false equivalences, perpetuates misinformation, and results in real societal harm. For example, see the framing of "the climate change debate" in popular media for decades. Furthermore, in such cases, some parties may passively benefit from such "neutrality", or even actively play a part in creating such a framing in bad faith.
Therefore, if you believe that you exist at a point in time when the oppressed have not had their side of history told, and your aim is to reach "the truth", whether for the sake of greater understanding or for the benefit of society, then it follows that you would need to counterbalance existing biases and even strategize against bad actors to reach the "truth".
It's entirely understandable then, that Zinn's attempts at bottom-up history would be valuable in their time, but if successful they would lose their significance, and their flaws would be more apparent, as new works would build upon, correct, and challenge them.
In that sense, I find Zinn similar to figures like Rachel Carson, who's work was revolutionary in her time, but today would be easy to find flaws in, dissect, and dismiss, but only because we have a better understanding of environmental issues and phenomena.
Anyway, my point is just that it doesn't seem fair to me to say that Zinn believed he served a "higher value than truth," it's not so simple.
" I was not going to be an objective historian, because I didn’t really believe objectivity was possible, nor was it desirable—unless objectivity meant telling the truth as you saw it, not lying, not distorting, not omitting information, and not omitting arguments because they don’t conform to some idea that you have. But if objectivity meant not taking a stand, if objectivity meant presenting data without caring about the social effect of the kind of data you present, at that—I didn’t want that kind of objectivity."
So, the beginning of the quote, which was the basis of the comment I answered, was an excerpt which suggested that he didn't believe in truth. The full quote shows that he was attempting to redefine the word 'objectivity' in order to make himself sound like an iconoclast, and in doing so declare that the general group of historians are shills. So, in a sense, his description of the historians of human history is like the one you've mentioned about Carson in your penultimate paragraph: he finds them easy to attack from his convenient position of hindsight.