It was all so matter of fact, not violent like back home but more measured and delivered without passion or feeling.
That’s a major difference between CP and abuse. The dispassionate, “matter of fact” approach, plus the fact that it applied to both sexes, suggests the teacher considered it a punishment for misbehaviour. It was like that at my school, it wasn’t a purely mechanical response but it wasn’t done in real anger either. Clearly, if one sex is completely exempt, regardless of their behaviour, it can’t be seen as a punishment for misbehaviour per se.
A lot a girls felt similar twinges watching boys (or even other girls) get it. That’s why, in schools where girls were exempt from CP, they would often contrive to get boys unjustly caned or slippered.