Let's go back to the speeding example.
Let's say you, the speeder, are RIGHT!
This is a country road, other similar portions of the road are posted 55 mph, there is no greater danger of "death or serious injury" from this stretch of road than from the other stretches that are posted 55 mph.
So you contact the County Commission, and you point out that it would make sense if this stretch of road was reposted from 25 to 55 mph.
The County Commission thanks you for your suggestion, but decides not to change the speed limit.
Do you believe that you personally are entitled to ignore the 25 mph posted speed limit?
Living in a republic governed by laws that derive from the collective consent of the governed has a lot of benefits. But it has a cost too - if you and those who think like you do are unable to change the laws you disagree with, you are still obligated to abide by them.
Bottom line. Are you willing to deprive your children from learning as much as they can because some beareaucrats say so?
If you don't think that this is a nonsensical, pointless, and potentially harmful (to the student's education) law then I don't know what to tell you.
And again, your speeding example is an entirely different animal. You cannot compare a law regulating how fast you can drive two-plus tons of machinery down a road with a law saying that teachers are forbidden from displaying flags in a geography classroom. I would hope that people here on FR would be able to make that distinction.