Since the public schools can't even teach the kids to read, write, spell and compute, why are we surprised at the lack of accuracy in the textbooks? Our schools have become unwieldy, inefficient bureaucracies dedicated to bigger budgets and hiring more administrative dead weight than last year.
In the best schools individual teachers have no autonomy in their classrooms and get saddled with the latest time-wasting fads promoted by special interest groups. In the worst schools teachers can't pass a simple, 7th grade level test, and the halls must be patrolled by security guards.
Having spent 4 years teaching in a public school that shared traits of both these two extremes I have to say your assessment is very accurate.