I think, given the condition of Travis by the time she left the house the day she slaughtered him, the dt is making a HUGE mistake in dwelling on this outpouring of hate from Travis. It's saying everything he had been saving up that describes how utterly depraved, evil, self-absorbed, manipulative, vile, and flat-out crazy she is. He is telling us from the grave what a waste of space she is and how truly capable she is of not only doing what she did to him, but NOT CARING one iota about what she did other than how it inconveniences HER.
He is even stating his own preference for how she should be sentenced. He says she is taking up other people's AIR. HE wants her to get the death penalty.
It's not often that the victim (the TRUE victim) in a case gets to give that kind of input in a trial.