Not in their culture, but in western culture it is. What country did this take place? Do you think in an Islamic country you would get away with an ignorance defense?
Jail them all for 7 years or offer sex change surgery and let them live a new life on a path to awakening!
Less philosophically: it's a man seeking to subjugate and humiliate a woman by using his sex parts. If he didn't have those parts, he'd use a broomstick. Castration won't work. The problem isn't what's between his legs, it's what's between his ears.