If you were sick, would you not be entitled to treatment? That's what we do in civilized societies, we treat the sick.
Anything else is taliban stuff. The taliban certainly would see it your way about killing the sick as a matter of principle and righteousness.
NO ONE who murders another human being is entitled to be set free by claiming some "victim" status for themselves. Clearly, every murderer could claim they are "mentally deficient", and we would have no room in all the "care" centers for them.
If anyone thinks this bitch did not know what she was doing, and that it was wrong, they cannot defend this act with some "mental" excuse.