Read her body language here. She's not stupid so much as a sociopath.
Looking to her right and away from eye contact she comes up with the following-
She says, "That tells us everything," yet is shaking her head "no," indicating she believes that statement is a lie.
"If we do not want violence on our subways" is a word choice that should coincide with a "no" shaking when she says "not" if she doesn't want that, instead gives us a "yes" head nod.
Some of her next few statements sandwich the appropriate head gestures around another contradictory set which indicates in this case a planned deception.
She starts shaking her head "no" before she even talks about the person committing manslaughter showing remorse, and continues to do so while saying it. She then moves on to the unintentional/innocent killer expressing remorse but shakes her head appropriately to the statement. Two things are going on here. She knows manslaughter is not intentional murder, though she's framing it that way, so she knows the entire premise-to-conclusion is a lie and she's caught herself in it.
People convicted of manslaughter (who kill someone unintentionally, but not entirely innocently, as their actions still caused it indirectly), may in fact show remorse. Yet she shakes her head "no" when talking about it.
The last few statements about "accountability" bring her body language back into agreement with each other, but that is a skillful correction meant to bolster her poor arguments given earlier and to somehow link that conclusion as something valid following directly from her statements.
She indicates she wants violence/lack of safety on the subways, and is trying to say that Penny will kill someone again, because he did it without remorse before. She knows he didn't intentionally kill him, as the jury rightly found, but she is creatively casting him in that light. That is what a sociopath does.
Ignored completely is that the man was not dead when released by Penny to the police, who refused to even attempt to save him.