He went too far.
But I don't see why teachers can't belt a misbehaving pupil as a last resort, and I'm still in college.
If their parents won't teach them discipline and respect(which they should also be punished for imo) then someone else has to I'm afraid.
It's not only a question of totally undermining and abusing not only a teacher but an adult but also affecting the education and mentality of almost 2 dozen other kids in the class who either get the idea this behaviour is acceptable or underachieve because they are not getting the adequate teaching because the teacher cannot teach and try to discipline in a diplomatic way with kids who have no intention of playing by the rules.
I probably sound traditionalistic but in reality there are so many rules on adults against kids, the kids get away with blue murder sometimes, it should work both ways.