That reminds me of a lot more problems I had. I remember one year on the very first day of class we had a teacher give us all a 'pre-test' for everything we were supposed to learn that year. Literally it was the first day of class and we were given a comprehensive final exam for the entire next year's curriculum. It was expected that everyone would fail, which most did.
Except me. I got either a 96% or 98% on that test. I think I missed two questions on the whole test. After we got the scores back I went to the teacher after class and made the case that I should be doing something else and not really do all that specific homework related to stuff I clearly already knew. Her response was that I should learn to take directions and that doing all the homework (she was known for giving excessive homework) would build my character. Naturally I thought the whole thing was bullshit and I quickly learned that school was not just about 'education' of what's in the books you get.
People might think that I should have been in the 'gifted and talented' program, but I WAS ALREADY IN the gifted and talented program. I aced the final exam of the math class for the gifted and talented program, on the first day of class.
I tell that story to demonstrate more than one problem and as a preface to this. Later on some school officials thought it was a smart idea to put the remedial students in class with the gifted students. Their logic was that the gifted students would rub off on the remedial ones and show them how to study or whatever. It fell flat on it's face though. Before the end of the year just about everyone saw a general decline in grades and behavior. All of my gifted and talented classmates all quickly became C level students and it happened in less than one school year.
One bad apple can ruin the bunch. You don't try to heal that apple. You get rid of it for the good of the rest. But the rules of school are not based on logic. They are REQUIRED to take everyone and anyone (and it shows).
The same general concept applies across a whole lot of things, behavioral and otherwise. If you take a Rhodes Scholar and put him in a classroom full of ghetto miscreants it won't take long for the scholar to join the ranks of his classmates.