>Main ideological information I learned in state schools: “there are these different ideologies” provided without judgement. There was even a devil’s advocate argument for the south and slavery.

Did you hear a "devil's advocate" argument for the burning of Tulsa, Oklahoma by white supremacists?

Both-Sides-Ism isn't a real way to account for ideological coercion in education. It's just painting a picture that includes your enemies. What your enemies look like in the picture is LADEN with ideology.