I’ve noticed too that most of the opposition to CP for girls seems to come from men but I don’t think it’s usually for the reason you give: although it might true be in a few cases. Some men will be hoping to ingratiate themselves with women in the, usually vain, hope of some “reward”. 
In most cases however, I think the true reason is to perpetuate the idea that we’re inferior to men. In some schools girls “only” got the slipper because the cane was considered too severe for us.
I wonder if there’s an analogue of Arrow’s Impossibility Theorem here?
Ideally, if you had sufficient knowledge about each pupil and his/her context, you would select a punishment which minimised the likelihood that the pupil would reoffend; or perhaps, which minimised the net likelihood and seriousness of all future offences (so that this would take account of the effect of punishing one pupil on the behaviour of others).