It's a system that works through sheer force of will, and squanders the efforts of educators and students alike. The ambition of education technology shouldn't be to rehabilitate 10 underserved students, no matter how noble of a goal that is. It should be to make sure they aren't ever underserved. The current system can't do that period.
By the time you have fixed the issues that prevent it from doing that, you've ripped out and replaced 90% of it. The way class progression works. Automating lecture components. The testing components. How responsibility over students is handed from teacher to teacher. Assuring best practices are used, both by students and teachers. The curricula and how they feed into each other. Tracking student progress. Negotiation of homework quantity between teachers. Enabling broad collaboration between teachers in matters of teaching materials. Quality assurance.
The rage is not against the fact that there is an education system. It's that it could be so much better. It's against the waste of youth. A class of 30 with only half of it engaged wastes 180 childyears over their K-12s. That's 2 long lifetimes, in the years when their minds are the most malleable.