I don’t know if anyone knows exactly what Bob is doing, but at a stab, he’s seeing how many unpleasant feelings get generated by imagining the crime, then proposing a jail sentence that activates about an equal amount of unpleasant feelings.
See the outrage heuristic, Kahneman & Frederick (2002) (pdf).
See the outrage heuristic, Kahneman & Frederick (2002) (pdf).