It relates to the concept of thinking 'we' are good/better/best, and 'they' are not, so don't buy their stuff! Time, past, different times/eras of development ought to be considered/remembered. Which is why I mentioned 'People's History'.
To criticize Zinn is changing the narrative.
History is written by the Victors. His People's History simply illuminates examples of what the Victors have done along the way to become and stay Victors. I could care less what his agenda is, he collected information I am glad I became aware of.
He Lies!!!
Uncle Tom's Cabin (how many have actually read it?) combined with the timing of the Fugutive Slave Act was far more important than I ever understood. Of course the Southerners said she lied, made things up, we don't do those things ....After a few years she issued a separate book with complete documentation of everything in her book. If you ever wondered how religion could support slavery, reading that book gives you those answers.
I am very thankful that I found and read it.