When I was 13, a girl kicked me in the shin in an aggressive, non-provoked way, drew blood and such, I then proceeded to punch her in the arm with all of my nerdy, Runescape-playing strength.
From that day on, I was branded a, "Woman beater" at school.
Even caused a few guys to knee me in my frontal thigh and shout "grandad" for some unknown reason.
I then got angry at the constant abuse from my peers and fought back, before long I was suspended for "Aggressive behaviour". Despite me "lying" about defending myself when provoked to. Was only for two weeks anyway.
So, I guess, they just wanted to have sex with her.
She was awfully fat and wore a ghastly amount of make-up, so I guess my peers assumed that she would offer them some form of sexual gift if they honored her bruised arm.
I can't honestly see any other reason than that.