Love that understatement.
Though, really, they didn't attack the attacker, they defended the life of the woman the attacker was attacking.
Reminds me of a Marine gunnery sergeant I met one time.
His car was parked at the curb in front of his house one night; he was asleep. CRASH!! He went to see what happened. He could see a van several doors down the street, stopped at a funny angle. As he rounded his own car he put his hand on the hood, and the car rocked. Hmmm, never seen that before he thought to himself (the van had hit his car so hard the frame was bent and the four wheels no longer all touched the ground.) He went to the van driver who had gotten out and was obviously drunk. I don't recall what led to the first punch, but the drunk took a swing at him.
The gunny cleaned his clock.
When the cop arrived, he saw the messed up drunk and asked what had happened.
Gunny, "He took a swing at me and I felt obliged to defend myself."
Cop, sarcastically, "Looks like you defended yourself pretty good."
Lesson: Don't pick a fight with a skinny, meek looking guy with a short haircut and bad attitude. He might just be Marine gunnery sergeant. Oh, and don't bash into his car, neither.
(The gunny was a pretty meek looking guy. I'd be surprised if he tipped the scales at more than 145lbs.)