i worked in education for 13 years, and that's bang on the money.Many years ago my Sons cousin was expelled from the RC school and was put into the non-sectarian school. The cousin was a rank bad one showing early stages of the behaviour we know them so well for.
At a parent/teacher night we expressed our concern that he might rope our Son into his antics and asked the teacher to keep a watch on him. The teacher in hushed tones told us it is standard practice for RC schools to dump unruly children and even under achieving kids to non RC schools to enhance their own performance ratings.
Vile and corrupt behaviour that I'm sure still goes on now. Perhaps this is why your Sons assailant does not attend the local bhigot factory.