US schools have far more surveillance

That depends. US schools are run by local (not even state) governments, usually towns, and there is huge diversity in what a school might look like.

Public schools in big cities (NYC, Philly, etc.) basically are prisons with wire fences, metal detectors, cameras everywhere, etc. I've seen a school with no windows -- it was designed this way so that there were no windows to break. But schools in e.g. rich suburbs are nice places, similar to college campuses.