I think the key question here is, why would that article title read differently? You and I can both agree that it *would* read differently, and that alone speaks volumes. The takeaway here isn't that violence against boys is ok. In this one instance, it very efficiently and elegantly solved a problem I was facing, but it's not like I've gone around kicking boys in the balls for the last 30 years. In fact, it's the only physical violence I've ever intentionally inflicted upon another human being, period, unless you count my sister.
The root of this story is the symbolism of taking an aggressor's source of power and turning it into a vulnerability. Men have used their genitals throughout human history to justify and inflict violence. The same simply cannot be said for women's faces...