The question I like to ask myself in instances like these, when I'm pissed off at what I see as unreasonable attitudes and processes, is this:
Do I care more about making myself feel better by airing my grievances in whatever way suits my fancy, or do I care about a specific outcome?
If it's the latter, then the best thing to do is to figure out who is in charge, and, critically, the right way to talk to them in order to get the response -- and hopefully the outcome -- I want.
Sure, I could turn this into a crusade to vote out the school board and replace them with... who, exactly? The kind of people who are qualified and likely to get elected are probably pretty similar to the people there already: not too technically-inclined, and not willing to put up with an aggressive attack from parents. Even if I did manage to find and elect a school board that would take this kind of issue seriously without needing much prodding, by the time I went through this whole process, it'll be... a year? Two years? More? The ship will have sailed, and my hypothetical kid will have leaked all their private data to the school's nanny software already.
So hopefully I'd instead do the smart thing, approach the school board in a way that resonates with them, and get the outcome I want.
> I've heard the same argument used for angry minority communities in the past
I don't think this really applies here. Most "angry minority communities" are fighting for things that are systemically stacked against them, and often the "polite" approach doesn't work. But we're not talking about systemic oppression here; we're talking about an overworked, underpaid school IT department that doesn't have much choice in what they do, directed by a school board that doesn't understand the issues involved.