I'm sorry, I didn't realize that facts needed more backing
You are simply factually incorrect about your assertion that higher grades are run the same as lower grades. I don't particularly care about your inability to accept that, but I do find it surprising that you would assert your inexperienced viewpoint is correct.
Also your insult was not missed. Thank you for that, it verifies to me that you have nothing of import to say.
While 'grade school' often refers to elementary school, surely you are aware of people's tendency to talk about 'k-12' education in a lump and the lax academic requirements for substitute teaching in many school districts even at high school level.