I wonder if his takeaway was that her life was not worth living, and this is an extension of that mindset.

Stage engineer: Fly system.

It’s also very often used as an argument against rehabilitation in prisons:

If free will exists, then crime is a choice. If you choose crime, you are a bad person, and punishment is the only way forward.

If you commit the crime again, it’s because the punishment didn’t work, and/or because the person is simply bad, so a longer punishment is needed, and infinitum.

It’s also used to justify the death penalty, which would not make any sense in a deterministic universe.