Um...
In the OP, there was one driver cited as being aggressive and causing problems. How many drivers patiently wait behind the kiddie peloton along that same stretch of road, all the time? And pass safely when safe to do so?
In my experience, it's 1 in 20 to 50 drivers who do something boneheaded on the road and I give them the benefit of the doubt -- might have been merely inattention or accidental, not something they do normally. It's when the same driver tries to kill me a second time in the same short span of an encounter that I take issue.
Truly aggressive drivers like the one in the OP, are in my experience, a rarity, maybe 1 in 1,000.
And guess what? Where are prime jerks in every walk of life -- why should the roads be any different?
The OP story is really great: driver thought they were in the right, took action, found out they were wrong, and the school made an issue -- a teaching opportunity -- about it.