I do agree a certain amount of knowledge should assessed to see if the child is ready for the next grade level.
And I think if the teacher is sending kids who are obviously behind to the next grade level is not doing anyone any favors and the teachers should obviously be fired .
I like the way some of the schools are starting to do it, were if they are a head in every other area except one subject they just go with a special teacher or even a younger grade class in the one area they are behind in. They also do it with students who are advanced.
I think it's dumb to expect every kid to be at the same level just because of their age. But I do think these teachers should be fired, they are suppose to be ethical example for these children and clearly aren't.