Most of todays HS History books were written by the communist Howard Zinn. His book 'A People's History of the United States" published in 1980 is used in HS across the country.

I dont have a WSJ account but this quote from a 2019 article is telling.

If you’re old enough to remember the Soviet Union, you’ve probably wondered why so many young people today seem attracted to socialism. One influence is Howard Zinn, who published “A People’s History of the United States” in 1980, the year before the first millennials were born.

Look at the wiki and read between the lines:

https://en.wikipedia.org/wiki/Howard_Zinn

From his biography:

Howard Zinn (August 24, 1922–January 27, 2010) was a historian, author, professor, playwright, and activist. His life’s work focused on a wide range of issues including race, class, war, and history, and touched the lives of countless people.

They dont even try to hide his communist beliefs.