Brought to you by the teachers' unions. Your kids are morons. We can't teach them. So no fair blaming us if they can't pass achievement tests. Just give us the raises for warehousing your brats and shut the hell up. And also parents of Bubba The Moron. My boy shouldn't be ranked against his peers. While everyone else is studying, he is winning football trophys for the school. So he deserves the same diploma as all the other kids, with no adverse grades attached.
Most of the rest of the world has figured this out already. Take the high achievers and move them into the fast track. Take the low achievers and send them to trade school. But Bubba doesn't want a diploma from Knuckle Draggers Acadamy when he has to go out and compete in the job market. And no teacher wants to teach there.