That's laudable, and what most people in the justice system probably work for. But go and talk to the people that system serves, i.e. the public, and I think you'll come out with a different understanding of what purposes punishment in the justice system serves.
Not to mince words, we've managed to humanize the justice system to a large extent, but by no means have we been able to remove the desire of the public to see criminals humiliated and deprived of their freedom, even lives, on tit-for-tat moral grounds. So, while the justice system in many 'civilized' countries does the best it can to be rational, in order to keep the public happy, it also needs to be seen to be sufficiently harsh on crime.