I don't see it as an indictment of the teachers, but the institution itself. I know many inspired teachers whose work ethic and selflessness can put us all to shame. There are also some pretty bad teachers. But neither point illustrates that the public education system (in the US at least) is engineered for many other concerns before considering how best to educate its students.
You can see it in this paraphrased anecdote from a middle school science teacher: The principal asks me to do a lot of things. Sometimes, he asks very sternly. However, as a teacher, there is only one thing I am legally required to do for these children every day: take attendance.
I don't think that quote means much of anything other than it's very difficult to legislate efficacy.
Suppose you had the absolute dream of a public education system -- one that existed solely to provide a real education for the children. What would the actual laws around that system look like? Is it a misdemeanor to make a D on a math test?
It also ignores that there are a wide range of well-meaning (but probably counterproductive) things we require of teachers that are for all intents and purposes legal requirements. If your kids perform too poorly on a test, your school may lose funding, for example. Again, I think that crosses the line beyond which such mandates make sense, but it's pretty clearly intended to improve the legitimate education your kids get. If it were about babysitting, they wouldn't bother.
In a vacuum, you're right, and it would be difficult to convey all the context that might sway you such that this anecdote is indicative of the structural problems in the education system. But this is just one of millions of anecdotes on how the system as a whole is largely concerned with anything but education.
The accounting machinery is needed to get money to all the schools sure, but when that accounting machinery becomes the focus of 40% of admins... You're not running an education system. You're moving money around that happens to educate...sometimes.
You can see it in this paraphrased anecdote from a middle school science teacher: The principal asks me to do a lot of things. Sometimes, he asks very sternly. However, as a teacher, there is only one thing I am legally required to do for these children every day: take attendance.