Finns are not more liberal about education because kids don't have to wear shoes, they are really conservative - the last country in Europe to create mandatory education and their spending on it is small. There is no need to pay more money to teachers so they can pay union dues so union employees can pay lobbyists to lobby the Education Department to use more federal taxes to redistribute it to schools.

Education is by rote.

They only go to grade 9. Why not extend it to make kids even smarter? It costs too much.

They don't spend a lot of time on social justice, they spend it on education. Kids who do not want to continue in academics go to "vocational" school. 

Teachers can be fired, so it is not a union entitlement occupation, it is instead a prestigious one because the public knows they are doing the job because they are the best at it. In America, education unions vilify young people right out of college who go into inner city schools to teach for low pay. They say these teachers are unqualified. What would make these bright educated college graduates "qualified"? Joining a union.

Why Finland’s kids often lead in educational tests - Science Codex