No one is saying that you need to or should go around punching people, but you should know how to throw a punch. Violence is a shitty path to take, but sometimes you have to throw one to protect the ones you love. It's not fair, but that's life. I'd rather know how to throw a punch and never have to do it than throw one and end up breaking my wrist.
I teach karate part time to preschoolers and kindergarteners. None of them know how to throw a punch except the girls. The boys try so hard to hit hard that their form is awful. They're hitting with their palm and knuckles, winding back so far that the bad guy would be gone by the time they punched. The girls, however, punch perfectly straight with great form. I don't know what it is, but men could certainly take a lesson from women on many things.