I agree that he should have been in jail, but I'm not sure how you conclude that he "should have fought back". He was practically a kid, and he'd never been in jail before - probably never encountered anyone like this in his life. It's hard to fault him for believing his life was in danger and for reacting the way he did.
I'm not faulting the kid, just wondering why he took it without resisting. There's no doubt the assailant should have been put in solitary after he attempted to assault the first inmate. But even 19 is old enough to know that you can resist a guy with no weapons. Maybe there was a substantial size disparity, I don't know, but giving in to empty threats is not the wisest course.
Why don't we blame the passengers on the 9/11 flights for not having fought back? They had the terrorists outnumbered no? Why even go to war over it when the passengers should have fought them off? This is a line of argument I don't think people want to go down. This rapist is obviously an ANIMAL- he's not human- and here this other guy is locked in a cage with him. I'm not going to blame him or second guess his actions. He's been violated and brutalized- it would be too much like cheering the rapist on to say the victim should've castrated him or whatever.