Because most people don't understand security in any way shape or form. Blocking everything is easier than trying to figure out what should be blocked, and what

Because most people don't understand security in any way shape or form. Blocking everything is easier than trying to figure out what should be blocked, and what shouldn't. I agree that it's better to ask them to unblock it on teacher accounts. But I can't do that, perhaps a teacher could. But I suspect that the tech admin that's stupid enough to block everything by default is the same type that's stupid enough to think that it's better security, and would just ignore then request to unblock it on teacher's computers. But I also have a nephew in school. What about when he asks me for help? Is he going to be able to ask the admin to unblock his computer?