Note that Wikipedia seems to be fawning over this piece of communist trash and that it has been used as a classroom book since 2008 in middle schools and High school classrooms.
http://www.historyisaweapon.com/zinnapeopleshistory.htmlAnother book in the same vein,
https://en.wikipedia.org/wiki/The_1619_Project
One effective method of finding the cause of things is called "5 Why".
The book you reference, as well as the 1619 content, would be revealed in the first Why or two. Somewhere around the answer to 5th or so Why it would be stated that Jews create and promote content of this sort, which is something that can be countermeasured by denying them further participation in our society via denial of the franchise to ethnic Jews.
Our children have been attending boot-camp for a long time.
The ones lucky enough to go to Uncle Sam university have had the proper training. This percentage is too small, always has been.
The rest have gone to the Marxist boot camp we have let our learning institutions become. It has happened right before our eyes. The opposition has been trained using our tax dollars and education system.
Remember when the push for college education became mandatory?
Trade schools and real-world experience have been removed as part of the equation. "You must attend college to be successful" - that is the current HS counselor stance. In the end, it only feeds the disillusionment agenda taught by the professors when the kids graduate and do not receive the promised riches and prosperity.
The education system must be vetted and rebuilt. The result is unmistakable. We must not only overcome this threat to our country right now, the institutions that have been working against America must be reclaimed.