[LaLaLand122]

This!

And as I did mention in another comment I still can barely believe the cases of bullying people describe here, they are horrible! I don't think bullying at such a level is a global problem. I suspect such huge bullying problems must be just a symptom of a deeper society issue. We had a kid with Down syndrome in class for 8 years of primary school and nobody did EVER put a finger on him. By 12 years old I had known my classmates my whole live, quite a few of them also from activities outside school. I didn't like all of them, we had arguments which were not always handled diplomatically, but we had some basic decency towards each other.

Bullying and whether kids should be separated by ability are two orthogonal problems.