Coming from someone who has done sysadmin work for schools, in practice the problem with filtering tends to come from the federal government requiring you to filter porn or else loose your funding, but doesn’t really provide any more guidance or resources beyond that.

Given most schools tend to be tight on money, this in practice means generally ticking the box’s in the firewalls config or outsourcing the whole system and the people who control the defaults control the vast majority of schools. No one person is going to try and keep track of and sort the entire internet, so often no one has any idea of what the ever updating list of blocked sites is until someone actually brings it up.

Personally I think the government should just set up a small board that maintains a repo with a list of sites they want blocked to comply with funding instead of leaving it up to the school, who will tend to be overzealous because there’s minimal to no cost one way and a massive one if it makes the news that you’re not strict enough.

This list of not safe for work sites could then even be used as the base of the filter for other government buildings too when combined with a data exfill list, and would save everyone a lot of time and effort. Of course it would likely hurt sales for a handful of companies with lobbyists and will never get done, but it would solve this issue.

All that being said, in the case of many of the schools listed in the article I have no trouble believing it’s malicious. The problem shouldn’t have taken more than a ticket or first talk with a sysadmin to resolve, much less escalated to legal action, and is undoubtly an active choice on the part of the school administrations in question.