You're right. But also consider that the current economy does not support this level of professionalism in teachers. Any teacher who can do a fantastic job meeting all of the expectations of students, teachers and administrators is smart enough to make 2x, 3x or more money in another profession with less stress.
I actually enjoy teaching more than programming and it's a better fit for me. But I choose programming because I can make 3x the money with half the effort. I'm not stressed out and I can pay the bills.
So keep that in mind the next time you confront a teacher. Even though you may technically be right, if you make their job harder, you may push them away from teaching. Remember, they could be a doctor, lawyer, engineer, or some other type of professional. We want to encourage highly intelligent and highly educated people to remain teachers, and if you give teachers a hard time, the only ones that will stick around are those who aren't able to find other jobs. Which aren't the kind of teachers you want.