It was always about regimentation, segregation by age and intellect, being taught instead of being allowed to learn, bells and whistles. Listen to your Commanding Office, I mean your Teacher!
https://en.wikipedia.org/wiki/Prussian_education_system
Early 19th-century American educators were also fascinated by German educational trends. In 1818, John Griscom gave a favorable report of Prussian education. English translations were made of French philosopher Victor Cousin's work, Report on the State of Public Education in Prussia. Calvin E. Stowe, Henry Barnard, Horace Mann, George Bancroft and Joseph Cogswell all had a vigorous interest in German education. The Prussian approach was used for example in the Michigan Constitution of 1835, which fully embraced the Prussian system by introducing a range of primary schools, secondary schools, and the University of Michigan itself, all administered by the state and supported with tax-based funding. However, the concepts in the Prussian reforms of primordial education, Bildung and its close interaction of education, society and nation-building are in conflict with some aspects of American state-sceptical libertarian thinking.[29]
In 1843, Mann traveled to Germany to investigate how the educational process worked. Upon his return to the United States, he incorporated his experiences in his advocacy for the common school movement in Massachusetts. Mann persuaded his fellow modernizers, especially those in his Whig Party, to legislate tax-supported elementary public education in their states. New York state soon set up the same method in 12 different schools on a trial basis. Most northern states adopted one version or another of the system he established in Massachusetts, especially the program for "normal schools" to train professional teachers.[30]
https://en.wikipedia.org/wiki/General_Education_Board
The Board was created in 1902 after John D. Rockefeller donated an initial $1,000,000 dollars to its cause. The Rockefeller family would eventually give over $180 million to fund the General Education Board. Prominent member Frederick Taylor Gates envisioned "The Country School of To-Morrow," wherein "young and old will be taught in practicable ways how to make rural life beautiful, intelligent, fruitful, re-creative, healthful, and joyous."[1] By 1934 the Board was making grants of $5.5 million a year. It spent nearly all its money by 1950 and closed in 1964.
https://en.wikipedia.org/wiki/Dumbing_down
https://en.wikipedia.org/wiki/John_Taylor_Gatto
He worked as a writer and held several odd jobs before borrowing his roommate's license to investigate teaching. Gatto also ran for the New York State Senate, 29th District in 1985 and 1988 as a member of the Conservative Party of New York against incumbent David Paterson.[4] He was named New York City Teacher of the Year in 1989, 1990, and 1991, and New York State Teacher of the Year in 1991.[3] In 1991, he wrote a letter announcing his retirement, titled I Quit, I Think,[5] to the op-ed pages of the Wall Street Journal, saying that he no longer wished to "hurt kids to make a living."