Did Matthew really deserve to die?
He was mentally challenged and was forced into raping her by Johnny and the others, he clearly said he didn't want to do it and they made him do it, so wasn't he in a way raped as well? he was forced to have sex against his will. And he was very upset and feeling guilty about the whole thing afterwards, he was even crying in her lap apologizing to her.
Surely for the rest of his life he would have been in a terrible mental state and felt regret every day he lived, wouldn't that have been punishment enough for him?
I guess you could say she let Matthew off the easiest cause he just got shot and died instantly but he didn't deserve to die at all, he got no pleasure or enjoyment out of what he was forced to do, he threw up after it and was scared.