spanglechick
High Empress of Dressing Up
it's a crude measure and it doesn't hold true in all circumstances - i remember seeing small guys physically taunted and bullied by heftier girls at school but knowing they couldn't hit back, 'cos of convention... but the reason the taboo is there is because of a generalised disparity in strength.
also spanglechick - i don't think the concern is only there for domestic/sexual abuse. people are pretty angsty about blokes fighting with women in pubs like they might do with other men. understandably.
But why. Why is that angst there with fighting women, and not little blokes?
The reason is patriarchy. Patriarchy is always a problem, even when it superficially advantages women. Treat women (but not skinny blokes) like delicate blossom, fragile and sacred... and you heap on them a whole load of indiscriminate baggage, a lot of which is actively detrimental (appropriate careers etc). The answer is not "yay, punch women", btw. The answer is "no! Don't punch anyone."