I don't think people appreciate how intractable a problem bullying is. For instance, bullying is qualitatively indistinguishable from teasing, which is regarded by most as part of normal, healthy socialisation. Hence low-level bullying goes unperceived. OTOH intense bullying is an embarrassment to the school statistics and hence frequently denied or covered up.

We live in a society where people still put a tremendous amount of effort into being normal and liked, and as a corollary we tend to persecute those who don't do this. Bullies are our unappointed henchmen.