He was writing about the civil rights movement, and accurately analysed COINTELPRO and other government repression. The teacher thought it was unfair characterization. So yeah, highschool’s are totally hubs of left wing indoctrination.
I was homeschooled for most of my education and I also didn’t have to deal with this bullshit! But in my case it’s probably because everything I was taught about Black history and race in America was thus:
“Black people were slaves and then they were freed by Christian Republicans. Atheist democrats then invented Jim Crow because evolution teaches that some races are inferior to others, and it lasted until MLK Jr (a Christian Republican) peacefully marched and ended systemic racism. Now the Democrats are oppressing Black people by giving them welfare and making them lazy while Black culture promotes drugs and violence.”
Homeschooling is fun because it turns out there’s nothing stopping your parents from using “textbooks” from the likes of Thomas Sowell and Dinesh D’Souza, and with heaping doses of the History Channel and the Bible to round things out.