I think I provided plenty of reasons why a typical school wouldn’t deal with open source. It’s not about something being “mandatory” or not. Schools have budgets and employees just like a company, and they don’t have specialized staff skilled in technology with ample free time to do all the extra configuration and management that most open source software demands.

Sure, they can purchase hosted enterprise versions of open source software. Of course, enterprise open source solutions have to compete on the same playing field as proprietary solutions (and many of them do! E.g. Gitlab).

Why should a school district care if there’s source code available? What are they going to do with it?

RMS subscribes to the flawed idea that the legitimately admirable ideals of FSF/GNU are important to everyone because they’re important to him. The idea that someone in charge of any organization, school, or business is going to make purchasing decisions based on ideology is somewhat naive.