I think you have more accounts like these from Catholic schools for several reasons. 1) It’s a huge organisation with enormous amounts of schools throughout history. It was the Catholic Church who started the consept of Universities and hospitals as well.
2) The Catholic church has always had a big problem with infiltration. The attempts to tear it down from the inside, by people who profess to be Christians, but are really enemies of Christianity, (freemasons and others) are vast.
3) Parents have tended to trust school staff more if they belong to the same religion. They have been willing to accept more weirdness, since education, religion and social life was so intertwined.
4) Pedophiles will always seek out places and organisations where they get to work with children. (Like the boys scouts and as gymnastic instructors) Many will be more than willing to fake religious adherence to be able to work with kids.
I grew up in a mostly protestant country, and the stories I have heard from state schools, by older relatives and neighbors, are also full of tales of physical and mental violence. Muslim and Jewish schools have been strict as well. The violence taking place in public schools in Scandinavia today are also terrible. Students have actually been murdered or raped by other students, while teachers have hardly any legal tools to stop it. It’s the opposite type of bad, I suppose. Anarchy-like sometimes. (There are of course big variations from school to school). And then you have the military type of school systems from some Asian countries.
The main problem is probably that people are being forced to go to school when they’re not happy there. Schools have too much power. And I think a lot of people have been pressured into monastic life when it wasn’t their calling. Some people just shouldn’t be teachers in the first place. Kids are always better off being around those who love them. Much better off than in institutions.